Selective cytopheresis devices and related methods thereof

ABSTRACT

The present invention relates to systems and devices to treat and/or prevent inflammatory conditions within a subject and to related methods. More particularly, the invention relates to systems, devices, and related methods that sequester leukocytes and/or platelets and then inhibit their inflammatory action.

RELATED APPLICATIONS

This application is a divisional of pending U.S. patent application Ser.No. 12/201,575, filed Aug. 29, 2008, which claims the benefit of andpriority to U.S. Provisional Patent Application Ser. No. 60/969,394,filed Aug. 31, 2007, the entire disclosure of which is incorporated byreference herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with government support under Grant Nos.DK080529 and DK074289 awarded by the National Institutes of Health. Thegovernment has certain rights in this invention.

FIELD OF THE INVENTION

The present invention relates to systems, devices, and methods to treatand/or prevent inflammatory conditions within a subject. Moreparticularly, the present invention relates to systems, devices, andrelated methods that sequester cells associated with inflammation, suchas leukocytes and platelets, and then reduce their inflammatoryactivity.

BACKGROUND

Various medical conditions are caused, exacerbated, and/or characterizedby unwanted inflammation. Infections, such as bacterial, viral, andfungal infections; trauma, such as from falls, automobile accidents, gunand knife wounds; cardiovascular events, such as aneurysms and ischemicevents often associated with surgery; and endogenous inflammatoryreactions, such as pancreatitis and nephritis, often lead to profounddysfunction of the homeostatic mechanisms involved in regulatingcardiovascular and immune system function. Several of these conditions,such as ischemia and infections, through abnormal or excessiveactivation of the immune system, may result in cardiovasculardysfunction that can develop over a period of hours to days, and which,under certain circumstances, can be life threatening or even fatal.

Certain cell types are critical to the dysfunction of the cardiovascularand immune systems. For example, leukocytes, especially neutrophils,contribute to the pathogenesis and progression of various inflammatoryconditions, including systemic inflammatory response syndrome (SIRS),sepsis, ischemia/reperfusion injury and ARDS (see, e.g., Kaneider et al.(2006) FEBS J 273:4416-4424; Maroszynska et al. (2000) Ann. Transplant.5(4):5-11). In addition, activated platelets enhance leukocyte adhesionand promote leukocyte activation. While inflammation and a systemicimmune response can be beneficial in certain circumstances, they canalso be fatal.

Inflammatory injury in organs can result in microvascular damage inducedby leukocyte activation and aggregation, as well as platelet activationand aggregation. These activated cells can contribute to microvascularstasis and reperfusion injury by releasing toxic compounds into apatient's tissue. In acute inflammation, activated leukocytes andplatelets interact as a gel-like structure within the vessel. This leadsto poor perfusion of the tissue, which normally is supplied with oxygenand nutrients by the capillaries. Activated leukocytes additionallycause damage by extravasating across the endothelium into the tissue,where they release toxic agents normally intended to destroy invadingmicrobes or clear out necrotic debris. Activated platelets additionallycause damage by enhancing the activation and endothelial transmigrationof leukocytes. When these processes are not controlled, they can lead totissue injury and death.

SIRS is the thirteenth leading cause of death in the United States ofAmerica. Severe sepsis with SIRS occurs in 200,000 patients annually inthe U.S. with a mortality rate of 30-40%, even with use of intensivecare units and broad spectrum antibiotics. SIRS is diagnosed largely onobserved physiological changes such as increase (fever) or decrease(hypothermia) in body temperature, increased heart rate (tachycardia),increased respiration rate (tachypnea), elevated or diminished whiteblood cell counts, and inadequate perfusion of tissues and organs. Adecrease in blood pressure is a complication associated with SIRS thatoccurs late in the course of the syndrome. Specifically, a decrease inblood pressure can reflect the development of shock and contribute tomultiple organ failure, which is a leading cause of death in thesepatients. Septic shock is a condition that includes the clinicalobservations of the presence of an infection and a drop in bloodpressure despite fluid resuscitation and proper cardiac blood output. Asimilar condition, sepsis syndrome, includes similar physiologicalsignals with no evidence of any type of infection. Other insults, whichinduce a sepsis-like condition include pancreatitis, burns, ischemia,multiple trauma and tissue injury (often due to surgeries andtransplants), haemorrhagic shock and immune-mediated organ dysfunction.

The standard therapies for SIRS and septic shock involve administrationof antibiotics to bring the infection under control and fluid/colloidtherapy to maintain circulating blood volume. Frequently, drugs thathelp maintain blood pressure, such as dopamine and vasopressin, are alsoadministered.

Cardiopulmonary bypass (CPB) strongly induces SIRS, activatingcomplement and coagulation systems and stimulating cytokine production.A large number of therapeutic approaches are under investigation tolimit the activation and accumulation of leukocytes during CPB. In fact,animal and early clinical data suggest amelioration of lung and kidneydamage during CPB surgery with the use of leukocyte depletion filters(see, e.g., Gu et al. (1996) J. Thorac. Cardiovasc. Surg. 112:494-500;Bolling et al. (1997) J. Thorac. Cardiovasc. Surg. 113:1081-1090; Tanget al. (2002) Ann. Thorac. Surg. 74:372-377; Alaoja et al. (2006) J.Thorac. Cardiovasc. Surg. 132:1339-1347). It appears, however, thatdialysis can produce transient neutropenia (see Kaplow et al. (1968)JAMA 203:1135).

Recent strategies for developing more targeted therapies for thetreatment of sepsis have been disappointing. In addition, many moleculesin the new generation of anti-septic agents are very expensive and canproduce adverse immunological and cardiovascular reactions, which makethem contra-indicated in some cases, such as non-bacteremic shock.

There remains a need for an effective treatment of inflammatoryconditions, such as, cardiovascular shock, sepsis, systemic inflammatoryresponse syndrome and anaphylaxis.

SUMMARY OF THE INVENTION

An inflammatory condition in a subject arises, in part, from theactivation of cells associated with inflammation, such as leukocytes andplatelets. The present invention relates to systems, devices, andmethods to treat and/or prevent this condition by sequesteringleukocytes or platelets and inhibiting or deactivating theirinflammatory action. The systems, devices, and methods of the inventionextracorporeally sequester one or both of leukocytes and platelets andinhibit their inflammatory actions. For example, these cells can bedeactivated and/or their release of pro-inflammatory substances can beinhibited. Although there are many ways to practice the invention, oneapproach is to sequester one or both of leukocytes and platelets in theinterior of a device providing a surface with which these cells mayassociate, and providing an agent capable of deactivating the cellsand/or inhibiting the release of a pro-inflammatory substance. In one,non-limiting embodiment, the device contains hollow fibers and the cellsassociate with the exterior of these fibers. Citrate is provided todeactivate the cells and/or prevent the release of a pro-inflammatorysubstance. Experiments conducted using this and other embodiments of thepresent invention provide unprecedented and surprising success inmaximizing subject survival. These results exemplify the compellingutility of the systems, devices, and methods of the invention across arange of inflammatory diseases and conditions.

Accordingly, in one aspect, the invention provides a system for treatingleukocytes that includes a device defining a passageway that permits abiological sample to flow therethrough and comprising a regionconfigured to sequester one or more leukocytes originating from thesample. The system also includes an agent capable of inhibiting therelease of a pro-inflammatory substance from the leukocyte ordeactivating the leukocyte.

This aspect of the invention can have one or more of the followingfeatures. The leukocyte can be activated and/or primed. The system canfurther include a second device in series with the device defining thepassageway. The agent can be associated with a surface of thepassageway. In certain circumstances, the agent can be infused into thepassageway. The agent can comprise an immunosuppressant, a serineleukocyte inhibitor, nitric oxide, a polymorphonuclear leukocyteinhibitor factor, a secretory leukocyte inhibitor, and a calciumchelating agent, wherein the calcium chelating agent can be citrate,sodium hexametaphosphate, ethylene diamine tetra-acetic acid (EDTA),triethylene tetramine, diethylene triamine, o-phenanthroline, or oxalicacid. However, the agent preferably is a calcium chelating agent, suchas citrate.

The region configured to sequester the leukocyte can include a membrane.The membrane can be porous, semi-porous, or non-porous and/or themembrane can have a surface area greater than about 0.2 m². The regionconfigured to sequester the leukocyte can be configured such that theshear force within the region is sufficiently low to allow the leukocyteto remain in the region longer than another component of the blood orfluid. For example, the shear force within the region configured tosequester the leukocyte can be less than about 1000 dynes/cm².Alternatively and/or in conjunction, the region configured to sequesterthe leukocyte can comprise a cell-adhesion molecule to allow theleukocyte to remain in the region longer than another component of theblood or fluid.

In another aspect, the invention provides a method for processing aleukocyte contained within a body fluid. The method includes (a)sequestering extracorporeally a primed or activated leukocyte, and (b)treating the leukocyte to inhibit the release of a pro-inflammatorysubstance from the leukocyte and/or deactivate the leukocyte. Thisaspect of the invention can have one or more of the following features.The leukocyte can be sequestered for a time sufficient to inhibitrelease of the pro-inflammatory substance from the leukocyte and/ordeactivate the leukocyte, and/or for a prolonged period of time, and/orfor at least one hour. The method can further comprise the step ofreturning the leukocyte produced in step (b) back to a subject. In step(b), a calcium chelating agent can be used to inhibit release of thepro-inflammatory substance and/or deactivate the leukocyte. Step (a) canbe performed using a device defining a passageway that comprises aregion configured to sequester the leukocyte.

In another aspect, the invention provides a method for treating asubject at risk of developing or having an inflammatory condition. Themethod comprises (a) sequestering extracorporeally a primed or activatedleukocyte from the subject and (b) treating the leukocyte to reduce therisk of developing inflammation associated with the inflammatorycondition or to alleviate inflammation associated with the inflammatorycondition. The inflammatory conditions that this method can treatinclude, but are not limited to, systemic inflammatory response syndrome(SIRS), cardiopulmonary bypass syndrome, acute respiratory distresssyndrome (ARDS), sepsis, rheumatoid arthritis, systemic lupuserythematosis, inflammatory bowel disease, multiple sclerosis,psoriasis, allograft rejection, asthma, chronic renal failure,cardiorenal syndrome, hepatorenal syndrome, acute organ failure fromischemic reperfusion injury to myocardium, central nervous system,liver, kidney, or pancreas, and acute organ failure due to toxic injury,for example, chemotherapy. Step (a) can be performed using a devicedefining a passageway, which comprises a region configured to sequesterthe leukocyte.

The systems, devices, and methods of the present invention are notlimited to a particular type or kind of leukocyte inhibiting agent. Insome embodiments, the leukocyte inhibiting agent is any agent that isable to inhibit release of a pro-inflammatory substance from theleukocyte and/or deactivate the leukocyte. Examples of leukocyteinhibiting agents include, but are not limited to, immunosuppressants,serine leukocyte inhibitors, nitric oxide, polymorphonuclear leukocyteinhibitor factor, and secretory leukocyte inhibitor. In someembodiments, the leukocyte inhibiting agent is a calcium chelating agent(e.g., citrate). The present invention is not limited to a particulartype or kind of calcium chelating agent, which include, but are notlimited to, citrate, sodium hexametaphosphate, ethylene diaminetetra-acetic acid (EDTA), triethylene tetramine, diethylene triamine,o-phenanthroline, oxalic acid and the like.

It is understood that any of the above-identified aspects or embodimentsof the present invention can be equally applied to the sequestration anddeactivation or inhibition of platelets (e.g., activated platelets), thecombination of leukocytes and platelets, or cells associated withinflammation. Accordingly, in another aspect, the invention provides amethod for treating a subject at risk of developing or having aninflammatory condition. The method comprises (a) selectivelysequestering extracorporeally a primed or activated cell associated withinflammation from the subject; and (b) treating the cell to reduce therisk of developing inflammation associated with the inflammatorycondition or to alleviate inflammation associated with the inflammatorycondition. In some embodiments, the activated cell associated withinflammation can be selected from the group consisting of a platelet anda leukocyte. In some embodiments, the primed cell associated withinflammation is a leukocyte.

It should be understood that different embodiments of the invention,including those described under different aspects of the invention, aremeant to be generally applicable to all aspects of the invention. Anyembodiment may be combined with any other embodiment unlessinappropriate. All examples are illustrative and non-limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and embodiments of the invention may be more fullyunderstood by reference to the following detailed description andclaims.

FIG. 1 is a schematic diagram of a section of an exemplary embodiment ofdevices in a system of the invention. In the Figure, (1) primedleukocytes from a subject's blood are (2) activated by an upstreamdevice in the system, for example, a hemofiltration device. In theupstream device, blood flows through the internal space of a hollowchamber and ultrafiltrate (UF) is filtered through the wall of thechamber. Upon exiting the first device, blood then flows inside a seconddevice, for example, a selective cytopheresis inhibitory device (SCID),along the outside of hollow fibers, while UF flows through the internalspace of the hollow fibers. The blood flowing along the outside of thehollow fibers is exposed to conditions (3) that permit leukocytes in theblood to be sequestered, for example, by adhering to the externalsurface of the hollow fibers, thereby facilitating (4) inhibition ofrelease of a pro-inflammatory substance from the leukocytes and/ordeactivation of the leukocytes with a leukocyte inhibiting agent, forexample, citrate, which decreases ionized calcium (Ca_(i)).

FIG. 2A is a schematic representation of an embodiment of a system ofthe invention comprising a SCID 555 that is the only device in thesystem and that includes an intracapillary space (ICS) with both endscapped. FIG. 2B is a schematic representation of an embodiment similarto FIG. 2A except that ultrafiltrate (UF) is collected from a SCID 655having only one end of the ICS capped. FIG. 2C is a schematicrepresentation of an embodiment of a system of the invention comprisinga first device, for example, a hemofiltration device 210, and a SCID 555that includes an ICS with both ends capped. FIG. 2D is a schematicrepresentation of an embodiment similar to FIG. 2C except thatultrafiltrate (UF) is collected from a SCID 655 having only one end ofthe ICS capped.

FIG. 3 is a schematic representation of an embodiment of a system of theinvention including a SCID 755 without a cap on its ICS.

FIGS. 4A-4F are schematic representations of embodiments of systemconfigurations of the present invention as utilized in a CPB circuit. InFIGS. 4A-4C, blood treated by a SCID 555 with the ICS capped at bothends (FIGS. 4A and 4B), or by a SCID 655 with one end capped, isrecirculated into the portion of the circuit prior to the venousreservoir 450 and oxygenator 460. In FIGS. 4D-4F, blood treated by aSCID 555 with the ICS capped at both ends is recombined with blood inthe portion of the circuit following the oxygenator 460. HF/HCrepresents a hemofilter/hemoconcentrator, P represents a pump 504, andUF represents a reservoir to collect ultrafiltrate.

FIG. 5 shows a schematic representation of an embodiment of a SCID 555of the present invention having an ICS with both ends capped.

FIG. 6 shows a schematic representation of an embodiment of a SCID 655of the present invention having an ICS with one end capped.

FIG. 7 shows a schematic representation of an embodiment of a SCID 755of the present invention having an ICS inlet 745 and ICS outlet 746,neither of which is capped.

FIG. 8 shows an additional embodiment of a SCID 855 of the presentinvention.

FIG. 9 shows the mean arterial pressure for porcine model groups treatedwith a system of the present invention, as described in Example 1.

FIG. 10 shows the cardiac output in porcine model groups treated with asystem of the present invention, as described in Example 1.

FIG. 11 shows hematocrit levels in porcine model groups treated with asystem of the present invention, as described in Example 1.

FIG. 12 shows survival curves of porcine model groups treated with asystem of the present invention, as described in Example 1.

FIG. 13 shows the average total white blood cell counts with time ofexposure to a SCID after bacterial challenge in each animal group (n=twoto three for each group), as described in Example 1.

FIGS. 14A-14D show light micrographs of a SCID containing hollow fibermembranes stained with H&E from three different animals. FIG. 14A is alow power micrograph showing adherent cells around each hollow fiber(160×). FIGS. 14B and 14C are higher power micrographs demonstratingleukocyte clustering along the outer surface of hollow fibers (400×).FIG. 14D is a high-power micrograph displaying predominantlypolymorphonuclear cells along with mononuclear cells in the adherentcell clusters (1600×).

FIG. 15 is a graph showing the difference in survival rate in subjectstreated with a SCID and either citrate or heparin treatment.

FIGS. 16A and 16B are graphs comparing the number of white blood cells(WBC) and neutrophils, respectively, in one pump and two pump systemconfigurations of the present invention.

FIG. 17 is a graph showing the amount of platelets in two exemplaryembodiments of system configurations of the present invention.

FIG. 18 is a graph showing the average myeloperoxidase (MPO) levels inanimals treated with either a SCID and citrate or a SCID and heparin.

FIG. 19 is a graph showing the expression of CD11b, a neutrophilmembrane protein responsible for neutrophil binding to endothelium, inanimals treated with either a SCID and citrate or a SCID and heparin.

FIG. 20 is a graph showing the number of neutrophils in the arterial andvenous lines of systems according to the present invention, in animalstreated with either a SCID and citrate or a SCID and heparin.

FIG. 21 is a graph showing the percentage of septic animals surviving asa function of time in animals treated with either a SCID and citrate ora SCID and heparin.

FIGS. 22A-22F are graphs showing the concentration of systemic totalwhite blood cells (WBC), systemic neutrophils, systemic lymphocytes,systemic monocytes, systemic eosinophils, and systemic platelets,respectively, in animals subjected to cardiopulmonary bypass surgery andtreated with a system of the present invention that included a SCID andcitrate.

FIGS. 23A and 23B are graphs showing systemic and circuit Ca_(i),respectively, in animals subjected to cardiopulmonary bypass surgery andtreated with a system of the present invention that included a SCID andcitrate.

DETAILED DESCRIPTION

Cells associated with inflammation, such as leukocytes (or white bloodcells) and platelets, normally defend the body against infection andinjury. However, many disease states and medical procedures can activateand/or prime these cells, which in turn can produce undesirable immuneand inflammatory responses that can be fatal. The present inventionrelates to systems and devices configured to treat and/or preventinflammatory conditions within a subject, and related methods. Thesystems, devices, and methods of the invention extracorporeallysequester one or both of leukocytes and platelets and inhibit theirinflammatory actions. Specifically, the present invention includessystems, devices, and methods for sequestering leukocytes, such asactivated and/or primed leukocytes, and inhibiting release of apro-inflammatory substance from the leukocytes and/or deactivating theleukocytes, before returning them to the subject. The present inventionalso includes systems, devices, and methods for sequestering other typesof cells associated with inflammation, such as platelets (e.g.,activated platelets) and inhibiting release of a pro-inflammatorysubstance from these cells, before returning them to the subject.

Although there are many ways to practice the invention, one way is tosequester one or both of leukocytes and platelets in the interior of adevice that provides a surface with which these cells may associate andto provide an agent capable of deactivating the cells and/or inhibitingrelease of a pro-inflammatory substance. In one, non-limitingembodiment, the device contains hollow fibers, and the cells associatewith the exterior of these fibers. Citrate is provided to deactivate thecells and/or prevent the release of a pro-inflammatory substance.Although the invention is described herein with regard to blood, theinvention is applicable to any biological sample that can flow throughan extracorporeal circuit, such as any fluid from a subject's bodycontaining these cells. Exemplary extracorporeal circuits are described,for example, in U.S. Pat. No. 6,561,997.

1. Overview

The systems, devices, and methods of the present invention arose fromthe unexpected observation that particular device and systemconfigurations not only can sequester activated and/or primed leukocytesbut also can inhibit their inflammatory activity, thereby reducing themulti-organ effects of inflammatory diseases and conditions, such assepsis and SIRS. These acute effects may also have an influence onchronic pro-inflammatory states, such as the chronic pro-inflammatorystate associated with end stage renal disease (ESRD). These systems,devices, and methods also showed effective sequestration of platelets.Experiments conducted using embodiments of the present invention provideunprecedented and surprising success in maximizing a subject's survival(see, for example, Example 3) and exemplify the compelling utility ofthese systems, devices, and methods across a range of diseases andconditions for therapeutic, diagnostic, and research applications.

A schematic representation of one exemplary embodiment is shown inFIG. 1. As shown, blood is exposed to a first device. Thereafter, theleukocytes become activated (and/or primed). The activated (and/orprimed) leukocytes then enter a device, generally referred to as aselective cytopheresis inhibitory device (SCID), wherein the activatedleukocytes are sequestered. It is understood that rather than beingactivated by a first device, the leukocytes may be activated (and/orprimed) as a result of a primary patient condition or secondary to othertypes of medical intervention.

In other words, in the SCID, the activated (and/or primed) leukocytesfrom the blood are sequestered, for example, by temporarily adhering toone or more surfaces inside the SCID. Sequestration of the leukocytescan be achieved by a variety of approaches, for example, by associationwith molecules in a passageway or passageway region in the SCID thatbind leukocytes, for example, activated and/or primed leukocytes, or bysetting blood flow within the device to provide low shear stress onleukocytes, allowing them to associate with one or more surfaces insidethe SCID. These sequestered leukocytes then are exposed to an agent, forexample, citrate, to deactivate the leukocytes or inhibit their releaseof pro-inflammatory substances. These systems and devices also can applyto other cell types, such as platelets.

Without being bound by theory, it is believed that calcium chelators,for example, citrate, lead to a low Ca_(i) environment in the device,inhibiting release of a pro-inflammatory substance from the leukocytesand/or deactivating the leukocytes. Pro-inflammatory substances mayinclude destructive enzymes and/or cytokines from the leukocytes. Thisinhibition and/or deactivation leads to an amelioration of theinflammatory state of the leukocytes. In this way, in the exemplaryembodiment shown in FIG. 1 (and other embodiments of the invention), theSCID sequesters leukocytes, for example, neutrophils and monocytes, andinhibits release of a pro-inflammatory substance from the leukocytesand/or deactivates the leukocytes, for example, with citrate and/or alow-Ca_(i) environment. The sequestration and inhibition and/ordeactivation of platelets can be achieved in a similar fashion.

It has been demonstrated that the addition of a calcium chelator, e.g.citrate, to a device of the present invention including a housingcontaining hollow fibers that sequester leukocytes had the unexpectedresult of improving a subject's innate immunologic system. Accordingly,the systems, devices, and methods of the present invention can treat orprevent a variety of inflammatory conditions (either as primary diseasestates or as a result of medical intervention) by directly treating asubject's blood that includes leukocytes (e.g., activated and/or primedleukocytes) or platelets (e.g., activated platelets). Followingtreatment, the blood is returned to the subject.

Moreover, any method, device, or system that sequesters leukocytes orplatelets (such as activated leukocytes, primed leukocytes, or activatedplatelets) and deactivates such cells or prevents such cells fromreleasing a pro-inflammatory substance can be used. Accordingly, thefollowing sections describe (1) configurations of systems that may beused to treat an inflammatory condition, (2) examples of how cellsassociated with inflammation can be sequestered, (3) examples of howsuch cells can be deactivated and/or inhibited from releasing apro-inflammatory substance, and (4) the inflammatory conditions that canbe treated using the methods, devices, and systems described herein.While the discussion in the sections that follow generally describesequestration and inhibition and/or deactivation of a particular celltype (e.g., leukocytes), it is understood that the same principles applyto the sequestration and inhibition and/or deactivation of other celltypes associated with inflammation (e.g., platelets, such as activatedplatelets).

2. System Configurations

As used herein, the term “cytopheresis” or “selective cytopheresis”refers to the sequestration of certain particles from blood. Selectivecytopheresis is used to sequester certain cells, such as leukocytes(e.g., activated and/or primed leukocytes) or platelets (e.g., activatedplatelets) from blood for purposes of facilitating inhibition of releaseof a pro-inflammatory substance from such cells and/or deactivation ofsuch cells. It should be understood that such inhibition and/ordeactivation can occur before, during, and/or after sequestration.

“Selective cytopheresis device,” “selective cytopheresis inhibitorydevice,” “SCD,” and “SCID” refer to embodiments of the present inventionthat sequester certain cells, such as leukocytes (e.g., activated and/orprimed leukocytes) or platelets (e.g., activated platelets). Theseembodiments can also deactivate and/or inhibit release ofpro-inflammatory substances from such cells before, during, and/or aftersequestration.

The systems of the present invention are configured to accomplishselective cytopheresis. In basic form, the system includes a SCID, afluid connection for blood to flow from a blood source (for example, asubject, such as a patient) to the SCID, and a fluid connection fortreated blood to flow from the SCID to a receptacle (for example, backto the subject). The SCID acts to sequester leukocytes, such asactivated and/or primed leukocytes, and facilitate inhibition of releaseof a pro-inflammatory substance from the leukocytes and/or deactivatethe leukocytes. Sequestration of leukocytes can be achieved by anytechnique described in Section 3 below. Inhibition of the release of apro-inflammatory substance from the leukocytes and/or deactivation ofthe leukocytes can be achieved by any technique described in Section 4below.

In some embodiments, a system can include a SCID, which optionally canalso perform other blood treatments, without additional treatmentdevices. See, for example, FIGS. 2A-2B and FIG. 8. Other embodiments ofa system can include a SCID, which optionally can perform other bloodtreatments, as well as additional devices that treat blood. See, forexample, FIGS. 2C-2D and FIGS. 4A-4F. For example, the additionaldevices can filter, oxygenate, or otherwise treat the blood before orafter the blood enters the SCID. Moreover, the SCID and/or additionaldevices in a system can include more than one component for treatingblood in other or complementary ways, for example, porous filters,oxygen pumps, and/or xenographic or allographic cells (for example,xenographic or allographic renal cells such as renal tubule cells). Insome embodiments, the device or devices in the system that facilitateselective cytopheresis are free of such additional components. Forexample, a SCID of the present invention may be free of cells such asxenographic or allographic cells (e.g., xenographic or allographic renalcells). These basic principles are described in more detail, below.

2.A. Single Device System

As mentioned, a system can contain a SCID to accomplish selectivecytopheresis and, optionally, other blood treatments without additionaltreatment devices in the system (see FIGS. 2A-2B). One embodiment ofsuch a SCID is shown schematically in FIG. 5. In FIG. 5, a SCID 555contains a plurality of porous membranes, which are hollow fibers 552(only one is labeled for clarity). The luminal space within these fibersis called the intracapillary space (“ICS”) 540. In this embodiment, theICS inlet and ICS outlet are capped 544. The space 542 surrounding thehollow fibers 552 and within a housing 554 of the SCID 555 is called theextracapillary space (“ECS”). Blood containing leukocytes enters the ECSinlet 548 and moves into the ECS 542 surrounding the fibers 552 (i.e.,moves into a passageway). Leukocytes are sequestered in the device, forexample, at the external surface of the hollow fibers 552, and exposedto an agent, for example citrate, capable of inhibiting release of apro-inflammatory substance from a leukocyte and/or deactivating aleukocyte. The agent can be infused into a line upstream of the ECSinlet 548 or may be infused into the SCID itself via a port.Alternatively, or in addition, the SCID can be prepared with the agent,prior to using the SCID. Flow rates in the ECS 542 are chosen in theranges described herein such that there is a low shear force (in theranges described herein) at the surface of the fiber 552 to allowleukocytes to associate therewith. In this way, inhibition and/ordeactivation of the leukocyte is achieved or initiated. Then, the bloodin the ECS exits the SCID via the ECS outlet 550, which enters into anoutflow line.

FIG. 2A shows the exemplary SCID 555 of FIG. 5 in a circuit according tothe invention. Blood from a subject enters a blood line and is movedthrough that line via a pump 204. On the same blood line, a leukocyteinhibiting agent (e.g., citrate) can be infused at a port 206,optionally with a pump. The blood in the blood line then enters the ECSinlet 548 and exits the SCID 555 at the ECS outlet 550. Blood lines atthe ECS inlet 548 and outlet 550, respectively, are attached using bloodline connectors with locking mechanisms 256. Leukocytes are shownsequestered in the ECS 542 at the external surface of the hollow fiber552. A blood outflow line from the ECS outlet 550 returns blood to thesubject. Another agent, such as calcium (e.g., calcium chloride orcalcium gluconate), can be infused at a port 258 on this blood outflowline to prepare the blood for re-entry into the subject. In certainembodiments, the ICS can contain xenographic or allographic cells, forexample, renal tubule cells, cultured in a monolayer on the lining ofthe ICS 540 of each fiber to further aid in treatment of the blood.However, in other embodiments, the ICS is cell-free. In the circuit ofFIG. 2A, the lumen 540 of the SCID 555 is filled with saline.

The circuit of FIG. 2B includes the same components as FIG. 2A andoperates in the same manner, except that FIG. 2B utilizes SCID 655 shownin FIG. 6 and ultrafiltrate is produced by this SCID 655. The SCID 655contains a plurality of porous membranes, which are hollow fibers 652.The luminal space within the fibers is the ICS 640 and the surroundingspace outside the fibers 652 and within the SCID housing 654 is the ECS642. Blood containing leukocytes enters the ECS inlet 648 and moves intothe ECS 642 surrounding the fibers 652 and exits at the ECS outlet 650.Leukocyte sequestration and inhibition and/or deactivation can beachieved as described above. However, in SCID 655, only the ICS inlet iscapped 644. The ICS outlet 646 is not capped. Accordingly, depending onthe characteristics of the porous hollow fibers 652 (e.g., permeabilityand pore size), a portion of the blood in the ECS 642 can pass acrossthe hollow fibers 652, and into the ICS 640 as ultrafiltrate (UF). Atube can be connected to the ICS outlet 646 for collecting ultrafiltrate(UF), which may be discarded as waste.

In another embodiment of a system with a single treatment device, theSCID can be a device as shown in FIG. 8. Blood enters one end 810 of theSCID 855 and travels through hollow fibers 802 through whichultrafiltrate passes into a hollow space 804. The filtered blood fromthe hollow fibers 802 passes into an ECS 806 and surrounds hollow fibers808 containing ultrafiltrate, which was passed from the hollow space804. The blood in the ECS flows over the hollow fibers 808 filled withultrafiltrate, and leukocytes are sequestered thereon. Flow rates arechosen in the ranges described herein to develop a shear force (in theranges described herein) at the surface of the ultrafiltrate hollowfibers 808 that permit leukocytes to associate with the fibers. Bloodultimately exits the device at a side port 812, and ultrafiltrate exitsas waste via an end port 813. The interior of the ultrafiltrate hollowfibers 808 optionally contain renal tubule cells. This embodiment of aSCID can be placed in a circuit as described for the SCID of FIGS.2A-2B.

Flow rates and membrane characteristics for the embodiments shown in thecircuits of FIGS. 2A-2B with the SCID of FIG. 5, 6, or 8 can be asdescribed below. For example, the ECS flow rate may be from about 100mL/minute to about 500 mL/minute. The flow rate of the ultrafiltratewaste (e.g., for the SCIDs shown in FIGS. 6 and 8) may include, forexample, flow rates from about 5 mL/minute to about 50 mL/minute.

2.B. Selective Cytopheresis Inhibitory Device as Part of a Hemodialysisor Hemofiltration System

As mentioned, in some embodiments the SCID is part of a system withother devices for treating blood. For example, the SCID can be a part ofa hemofiltration system, a hemodialysis system and/or ahemodiafiltration system that includes one or more filtration cartridgesseparate from the SCID within the system. When describing the part ofthe system that is not the SCID, the term “hemofiltration” can refer tohemodialysis, hemodiafiltration, hemofiltration, and/orhemoconcentration and “hemofilter” can include a device (e.g., acartridge) for performing one or more of hemodialysis,hemodiafiltration, hemofiltration, and/or hemoconcentration. Thehemofiltration cartridge(s) can be configured to be in parallel orseries with a SCID within an extracorporeal blood circuit, andassociated blood pumps and tubing can be used to move the blood throughthe extracorporeal circuit. For example, as shown in FIGS. 2C and 2D,blood flows from a subject through a blood line. The blood is movedthrough the blood line via a pump 204. A leukocyte inhibiting agent(e.g., citrate) can be infused into the same blood line at a port 206,optionally with a pump. The blood then flows through hollow fibers 214in a conventional hemofilter 210. Dialysate is infused into the ECSsurrounding the hollow fibers 214 and within the hemofilter 210 housing,and dialysis occurs with solutes being removed as “waste” from the bloodacross the hemofilter filtration membrane 214 (the hollow fibers) andinto the dialysate. The dialysate flows in a counter current fashionrelative to the blood, and the dialysate is moved with a dialysate pump218. Additionally, molecules and fluid from the blood can pass acrossthe hemofilter filtration membrane 214 (the hollow fibers) asultrafiltrate, depending on the pore size through the membrane.

The exemplary system of FIG. 2C shows a circuit with the SCID 555 ofFIG. 5. Blood exits the hemofilter 210 and enters the SCID 555 at theECS inlet 548. The blood then is processed through the SCID, whichsequesters leukocytes on the hollow fibers 552 and inhibits release of apro-inflammatory substance from a leukocyte and/or deactivates aleukocyte in the manner described for FIGS. 2A-2B, above. The bloodlines into and out of the SCID 555 are attached using a connection witha locking mechanism 256. The blood is then returned to the subject via ablood outflow line from the ECS outlet 550. Another agent, such ascalcium, can be infused at a port 258 on the this blood outflow line inorder to prepare the blood for re-entry into the subject. In certainembodiments, the intracapillary space (ICS) of the SCID can containxenographic or allographic cells, for example, renal tubule cells,cultured in a monolayer on the lining of the lumen of each fiber tofurther aid in treatment of the blood. However, in other embodiments theICS is cell free. In the circuit of FIG. 2C, the ICS 540 of the SCID 555is filled with saline and the end ports of the ICS are capped 544.

The circuit of FIG. 2D includes the same components as FIG. 2C andoperates in the same manner, except that FIG. 2D utilizes the SCID 655of FIG. 6 and ultrafiltrate is produced by this SCID 655. The flow ofblood through the SCID 655 is described above in the context of FIG. 2B.Additionally, SCID 655 functions as described above, in the context ofFIG. 2B. As noted above, SCID 655 has only the ICS inlet capped 644. TheICS outlet 646 is not capped. Accordingly, depending on thecharacteristics of the porous hollow fibers 652, a portion of the bloodin the ECS 642 can pass across the hollow fibers 652, and into the ICSas ultrafiltrate (UF). A tube can be connected to the ICS outlet 646 forcollecting ultrafiltrate (UF), which may be discarded as waste.

Without wishing to be bound by theory, it is contemplated that the flowgeometry in these embodiments of the SCID system (and those shown inFIGS. 1, 2A-2B, 3, and 4A-4F) allows leukocytes to exist in a low shearforce environment in the ECS of the SCID and, therefore, associate withone or more internal surfaces in the SCID, for example, the hollowfibers. Conversely, in a typical use of a hemofiltration cartridge (forexample, the first device 210 in the circuits of FIGS. 2C and 2D), bloodflow through the small diameter lumens of the hollow fibers yields ahigher shear force (than that in the SCID) that prohibits association ofleukocytes with the hollow fibers and sequestration of leukocytes withinthe device. Accordingly, a hemofiltration device having the conventionalflow circuit supporting its operation reversed (i.e., blood flowingoutside the hollow fibers rather than inside the hollow fibers) can actas a SCID to sequester potentially damaging and circulating activatedleukocytes. These sequestered leukocytes can be treated with a leukocyteinhibiting agent (e.g. citrate).

Further, it is contemplated that the inflammatory response ofsequestered leukocytes is inhibited and/or deactivated in the presenceof low Ca_(i) (caused, for example, by citrate) before, during, and/orafter sequestration. The low-Ca_(i) environment may inhibit theinflammatory activity of, or deactivate, the leukocytes.

In certain embodiments, rather than both dialysate and ultrafiltratebeing produced by the hemofilter (e.g., the hemofilter 210 of FIGS. 2Cand 2D), only ultrafiltrate is produced. During ultrafiltration, bloodis separated into ultrafiltrate, which has been filtered through amedium, such as a membrane, and a retentate, which does not pass throughthe medium. One example of this type of system is the SCID 755 of FIG. 7in the system of FIG. 3. Briefly, in this system the blood flows inthrough the ECS inlet 748 of the SCID 755, into the ECS 742 defined bythe SCID housing 754 and hollow fibers 752, and out through the ECSoutlet 750 in the SCID 755. Additionally, an ultrafiltrate line 320 fromthe hemofilter 210 is in communication with the ICS 740 of the SCID 755via an ICS inlet 745 and provides ultrafiltrate to the ICS 740. Thefiltered blood (in the ECS 742) and the ultrafiltrate (in the ICS 740)are separate but can interact with one another across the membranes ofthe hollow fibers 752. The ultrafiltrate in the ICS 740 and the filteredblood in the ECS 742 of the SCID 755 can flow in a cocurrent orcountercurrent manner. Processed ultrafiltrate exits the ICS 740 at theICS outlet 746 of the SCID 755 and can be discarded as a waste product.Accordingly, in this embodiment, the ICS inlet 745 and ICS outlet 746are not capped, but the SCID 755 is otherwise substantially the same asthe one shown in FIG. 5 and FIG. 6.

More particularly, in the system of FIG. 3 using the SCID 755 accordingto FIG. 7, blood is moved from a subject (for example, a patient or anyanimal) in a blood line. Blood is pumped through the blood line with apump 204. A leukocyte inhibiting agent, such as citrate, can be infusedat port 206, optionally with a pump. The blood then enters hollow fibersof a hemofilter 210 and deposited into the ECS of the hemofilter 210 ina manner described for FIGS. 2C-2D above. Ultrafiltrate is producedacross the hollow fibers of the hemofilter 210 and is deposited into theECS of the hemofilter 210. The ultrafiltrate then passes through anultrafiltrate line 320 from the hemofilter 210 and enters the SCID 755at an ICS inlet 745. The ultrafiltrate moves through the ICS 740 of thehollow fibers 752 and exits at the ICS outlet 746. The hollow fibers canbe porous, semi-porous, or non-porous membranes.

The filtered blood remaining in the ICS of the hollow fibers of thehemofilter 210 (i.e., the lumens of the hollow fibers in the hemofilter210) exits the hemofilter 210 and is pumped with pump 300 into the ECSinlet 748 of the SCID 755. Optionally, this pump can be placed on theblood line between the SCID and the subject or a third pump (not shown)can be placed on the blood line between the SCID and the subject. Theblood flows into the ECS 742 surrounding the hollow fibers 752 (i.e.,moves in a passageway). Leukocytes, such as activated and/or primedleukocytes, are sequestered in the device, for example, at the externalsurface of the hollow fibers 752. Blood then exits the SCID 755 at theECS outlet 750 and returns to the subject. Blood line connectors 256with a locking mechanism attach the blood lines to the ECS inlet 748 andthe ECS outlet 750. Another agent, such as calcium, can be infused at aport 258 on the blood outflow line returning to the subject to preparethe blood for re-entry into the subject. Also, an ultrafiltrate pump 304moves ultrafiltrate from the ICS 740 to waste. However, depending on thepump flow rates in the system, none, some, or all of the ultrafiltratecan cross the hollow fibers 752 and return to the filtered blood in theECS 742.

The use of the SCID of FIG. 7 in the circuit shown in FIG. 3 has beenevaluated in over 100 large animals in pre-clinical testing and innearly 100 patients in Phase I, IIa, and IIb clinical studies with nounanticipated adverse events related to the SCID and the perfusioncircuit. Although the ICS can be cell free, it is understood that thissystem optionally also can include cells within the ICS 740, for examplerenal tubule cells. The rate of the blood flow is chosen to have asufficiently low shear force (in the ranges described herein) at thesurface of the porous, hollow fibers to allow sequestration ofleukocytes by association with the fibers, for example at a blood flowrate from about 100 mL/minute to about 500 mL/minute. Alternatively, theblood flow rate through the extracorporeal circuit, through the lumensof the hollow fibers in the hemofilter 210, and through the ECS 742 ofthe SCID 755 can be about 120 mL/minute. The ultrafiltrate can be movedat rates in the ranges described herein, for example, at flow rates lessthan about 50 mL/minute, from about 5 mL/minute to about 50 mL/minute,and from about 10 mL/minute to about 20 mL/minute. Alternatively, theultrafiltrate flow rate can be maintained at 15 mL/minute. Optionally, abalanced electrolyte replacement solution (e.g., a solution containingbicarbonate base) can be infused into the bloodline on a 1:1 volumereplacement for ultrafiltrate produced. The fluid (e.g., ultrafiltrate)and blood (or leukocyte-containing fluid) can flow in the same directionor in opposite directions.

In this and other embodiments, the blood flow configuration through theSCID is opposite the blood flow configuration through a typicalhemofiltration cartridge. That is, blood flows through the interior ofthe hollow fibers of the hemofiltration cartridge in its intended useversus around the outside of the hollow fibers of the SCID. Thisunconventional blood flow configuration through the SCID allows for alower shear force within the ECS at the exterior surface of the hollowfiber relative to the higher shear force within the lumen of the hollowfibers of a hemofilter, thus facilitating sequestration of leukocytes inthe ECS of the SCID. Conversely, the blood flow through the interior ofthe hollow fibers of the hemofilter prohibits leukocyte sequestrationdue to high shear force created by blood flowing through the smalldiameter lumens of the hollow fibers. For example, tests have shown thatblood within the interior of a hollow fiber of a hemofilter creates ashear force of 1.5×10⁷ dynes/cm² while blood flow through the ECS ofcertain embodiments of a SCID creates a shear force of 5.77 dynes/cm²,or 10⁶ less shear force. For comparison, the shear force at a typicalarterial wall is 6 to 40 dynes/cm² and the shear force at a typical veinwall is 1-5 dynes/cm². Thus, a capillary wall has a shear stress of lessthan 5 dynes/cm².

Accordingly, in some embodiments, the present invention uses asufficiently low shear force at a surface in a region of a passagewayconfigured to sequester leukocytes to be able to associate leukocyteswith that surface and sequester leukocytes, such as activated and/orprimed leukocytes in the region. For example, in some embodiments ashear force of less than 1000 dynes/cm², or less than 500 dynes/cm², orless than 100 dynes/cm², or less than 10 dynes/cm², or less than 5dynes/cm², is useful at a surface in the passageway region configured tosequester leukocytes. It should be understood that these shear forcesmay be useful in any of the SCID embodiments described herein. Incertain embodiments, having two devices, such as a hemofilter and aSCID, the difference in shear force between blood flowing in thehemofilter and blood flowing in the SCID can be at least 1000 dynes/cm².

In these and other embodiments, so long as the unconventional flowconfiguration is followed (i.e., blood flows outside of the hollowfibers, rather than inside the hollow fibers) to yield the requisiteshear force, the SCID can be comprised of a conventional 0.7 m²polysulfone hemofilter (e.g., Model F40, Fresenius Medical Care NorthAmerica, Waltham, Mass., U.S.A.), which is approved by the FDA for usein acute and chronic hemodialysis. Similarly, the extracorporealperfusion circuit of this or any other embodiment can use standarddialysis arteriovenous blood tubing. The cartridges and blood tubing canbe placed in any dialysate delivery pump system (e.g., Fresenius 2008H)that is currently in use for chronic dialysis.

In one exemplary system, the system includes tubing leading from asubject (a blood line) with a bag of a citrate solution infused into thetubing by an infuser. A first F40 hemofilter cartridge is connected withthe blood line at a point after the citrate enters the blood line. Bloodin the blood line then flows through the interior of hollow fibers (theICS) inside the cartridge, from an end port inlet to an end port outlet,and dialysate flows outside these hollow fibers and within the cartridge(the ECS) from one side port to a second side port in a countercurrentmanner with respect to the blood flow. A dialysate/ultrafiltrate mixtureexiting from the second side port is collected. Substantially no bloodcells, platelets, or plasma cross from the ICS to the ECS, andsubstantially no leukocytes adhere to the interior of the hollow fibers.The hollow fibers are disposed parallel to one another in a bundle, andeach fiber has a diameter of approximately 240 micrometers. Furthermore,the pores of the hollow fibers are small enough to prevent passage ofalbumin, a molecule of about 30 angstroms, through the fibers, and thepores are generally this size across the entire fiber. The filteredblood then continues from the end port outlet, through tubing, to a sideport inlet of a second F40 cartridge (i.e., the SCID). The blood flowsthrough the ECS of the second F40 cartridge and exits the cartridge at aside port outlet. Any ultrafiltrate that is produced in the second F40cartridge enters the ICS and exits through an end port. The other endport of the cartridge is capped. Substantially no blood cells,platelets, or plasma cross from the ECS to the ICS, and leukocytesadhere to the exterior of the hollow fibers for some period of time.Blood exiting the second F40 cartridge enters tubing where a calciumsolution is infused into the blood using an infuser. Finally, the tubingreturns the processed blood to the subject. In certain embodiments, theblood flow rate in the system does not exceed 500 mL/minute, and blooddoes not displace air in the system at any point. Additionally, thepumping and infusion rates can be manually changed in view of bedsidereadings of electrolytes and white blood cell counts. An i-STAT®handheld monitoring device produces these readings from a small amountof blood withdrawn from the subject.

The risk of using such a system is similar to the risk associated withhemodialysis treatment and includes, for example, clotting of theperfusion circuit, air entry into the circuit, catheter or blood tubingkinking or disconnection, and temperature dysregulation. However,dialysis machines and associated dialysis blood perfusion sets have beendesigned to identify these problems during treatment with alarm systemsand to mitigate any clot or air embolism to the subject with clotfilters and air bubble traps. These pump systems and blood tubing setsare FDA approved for this treatment indication.

As mentioned above, infusion of a leukocyte inhibition agent, forexample, citrate, can be local to the SCID, regional, or throughout thesystem. In this or any embodiment, citrate can also be used as ananti-clotting agent, in which case perfusion throughout the system wouldbe useful. Clinical experiences suggest that if clotting occurs within ahemofiltration system, it is initiated in the first dialysis cartridge.Anticoagulation protocols, such as systemic heparin or regional citrate,are currently established and routinely used in clinical hemodialysis.

2. C. Selective Cytopheresis Inhibitory Device as Part of aCardiopulmonary Bypass System

As shown in FIGS. 4A-4F and as described in Examples 8 and 9 herein, aSCID can be used within a cardiopulmonary bypass (CPB) circuit to treatand/or prevent inflammatory conditions secondary to surgeries (e.g.,bypass surgery). FIGS. 4A, 4B, 4D, 4E, and 4F show the SCID of FIG. 5 inexemplary CPB systems. FIG. 4C shows the SCID of FIG. 6 in an exemplaryCPB system. CPB is used to divert blood from both the left and rightsides of the heart and lungs. This is achieved by draining blood fromthe right side of the heart and perfusing the arterial circulation.However, since systemic-to-pulmonary collaterals, systemic-to-systemiccollaterals, and surgical site bleeding return blood to the left side ofthe heart, special drainage mechanisms of the left side of the heart arerequired during CPB. Optionally, cardioplegia can be delivered through aspecial pump and tubing mechanism. A standard CPB system has severalfeatures that can be broadly classified into three subsystems. The firstsubsystem is an oxygenating-ventilating subsystem that supplies oxygenand removes carbon dioxide from the blood. The second subsystem is atemperature control system. The third subsystem includes in-linemonitors and safety devices.

As shown in the embodiment of FIG. 4A, blood is moved via a venouscannula 400 from a subject into a blood line 410. Blood flows throughthe blood line 410, passing a recirculation junction 420, which isconnected to a SCID outflow line 430. The SCID outflow line 430 containsblood treated by the SCID device 555. The blood in the blood line 410mixes with the SCID-treated blood and continues to a venous reservoir450 and onto an oxygenator 460 where the blood is oxygenated. Theoxygenated blood then flows from the oxygenator 460 to a junction 470with a SCID inflow line 480. Here, where a portion of the blood in theblood line 410 is diverted to the SCID 555 via the SCID inflow line 480for treatment by the SCID 555. The flow of blood through the SCID inflowline 480 is controlled by a pump 504. The SCID 555 is designed tosequester select cells associated with inflammation, for example,leukocytes or platelets. In this embodiment, no leukocyte inhibitingagent is added to the blood entering the SCID 555. Blood containingleukocytes enters the ECS inlet 548 and moves into the ECS 542surrounding the hollow fibers 552. Leukocytes are sequestered in thedevice, for example, at the external surface of the hollow fibers 552.Flow rates at pump 504 can be chosen at ranges described herein suchthat there is a low shear force (in the ranges described herein) at thesurface of the hollow fibers 552 to allow leukocytes to associatetherewith. Blood in the ECS 542 exits the SCID via the ECS outlet 550and enters the SCID outflow line 430. At junction 470, a portion of theblood in the blood line 410 also continues to an arterial filter/bubbletrap 490, before being returned to the subject at an arterial cannula495.

The circuit in FIG. 4B flows in the same fashion as the circuit in FIG.4A, with the additional features of a citrate feed 435 and citrate pump436 to add citrate to the blood in the SCID inflow line 480 and acalcium feed 445 and calcium pump 446 to add calcium to the blood in theSCID outflow line 430. Citrate (or another leukocyte inhibiting agentdescribed herein) is added to the blood flowing into the SCID 555 fromthe citrate feed 435 to inhibit and/or deactivate cells associated withinflammation, such as leukocytes. Calcium can be added back into theblood to prepare the blood for reentry into the subject.

The circuit in FIG. 4C functions in a similar fashion as the circuit inFIG. 4B, with additional features associated with ahemofilter/hemoconcentrator (HF/HC) 476. Specifically, the portion ofthe oxygenated blood that is diverted at junction 470 toward the SCID655 via the SCID inflow line 480 is further split at junction 472 into aportion that flows to the SCID 655 and a separate portion that flows tothe HF/HC 476 via a HF/HC inflow line 474. The HF/HC can filter orconcentrate the blood, with ultrafiltrate passing from the device via awaste tube 477. The filtered or concentrated blood exits the HF/HC 476via a HF/HC outflow line 479 that returns the filtered or concentratedblood to the SCID outflow line 430 at a junction 444. The SCID shown inFIG. 4C is the SCID of FIG. 6, as described above. Blood flows from theSCID inflow line 480, into the ECS inlet 648, through the ECS, out theECS outlet 650, and into the SCID outflow line 430. Ultrafiltrate may beproduced across the hollow fibers in the SCID (from the ECS to the ICS),with ultrafiltrate passing from the SCID at the ICS outlet 646 into awaste tube 478.

Blood flow to the SCID 655 can be controlled by the pump 504. Pump 504is preferred to maintain constant flow in embodiments that infuseagents, such as citrate, that inhibit or deactivate the leukocytes,and/or another agent, such as calcium, following SCID treatment.Alternatively, blood flow to the SCID can be controlled by selecting asmaller caliber of the SCID inflow line 480 between junction 472 and theSCID 655 relative to the caliber of the HF/HC inflow line 474, so thatonly about 200 mL/5 L (about 4% of the flow volume) is diverted to theSCID at the junction 472. This results in low shear force in the SCID,which can facilitate sequestration.

The circuits shown in FIGS. 4D-4F are different from the circuits ofFIGS. 4A-4C in that they do not recirculate blood within the circuit,for example, at a recirculation junction 420. Rather, as shown in FIG.4D, blood is moved via the venous cannula 400 from a subject into theblood line 410, where the blood flows directly to the venous reservoir450 and onto an oxygenator 460 where the blood is oxygenated. Theoxygenated blood then flows from the oxygenator 460 to the junction 470with the SCID inflow line 480. Here, a portion of the blood in the bloodline 410 is diverted to the SCID 555 via the SCID inflow line 480 forsequestration of leukocytes by the SCID 555, as described above for FIG.4A. Blood exiting the SCID 555 enters the SCID outflow line 430 andmixes with oxygenated blood at junction 422. After blood from the SCIDmixes with blood in the blood line 410 it continues in the blood line410 to the arterial filter/bubble trap 490, before being returned to thesubject at the arterial cannula 495.

The circuit in FIG. 4E flows in the same fashion as the circuit in FIG.4D, with the additional features of a citrate feed 435 and citrate pump436 to add citrate to the blood in the SCID inflow line 480 and acalcium feed 445 and calcium pump 446 to add calcium to the blood in theSCID outflow line 430. As described for FIG. 4B, citrate or any otherleukocyte inhibiting agent is added to the blood from the citrate feed435 to inhibit and/or deactivate cells associated with inflammation,such as leukocytes. Calcium can be added back into the blood to preparethe blood for reentry into the subject.

The circuit in FIG. 4F flows in a similar fashion as the circuit in FIG.4E, except that the junction that diverts a portion of the blood fromthe blood line 410 to the SCID inflow line 480 and the junction whichreturns SCID-treated blood via the SCID outflow line 430 to thebloodflow line 410, are positioned after the arterial filter/bubble trap490 in the circuit. These junctions are labeled 492 and 494,respectively. FIG. 4F also depicts other subsystems and features, suchas heat exchangers, additional pumps, gas meters and exchangers, andmonitors, that can be used in any of the above-identified embodiments.Moreover, the SCID in any of the embodiments described in FIGS. 4A-4Fcan be configured with characteristics (e.g., configurations of devicessuch as the SCID, membrane characteristics, flow rates) in accordancewith any embodiment described herein.

2.D. Additional Features of Selective Cytopheresis Inhibitory Devices

In some embodiments, the devices of the present invention are configuredfor treating and/or preventing a certain disorder. It is understood,however, that a number of different configurations can be used to treatand/or prevent a particular disorder.

Moreover, the SCID of any embodiment can be oriented horizontally orvertically and placed in a temperature controlled environment. Thetemperature of a SCID containing cells preferably is maintained at about37° C. to about 38° C. throughout the SCID's operation to ensure optimalfunction of the cells in the SCID. For example, but without limitation,a warming blanket may be used to keep the SCID at the appropriatetemperature. If other devices are utilized in the system, differenttemperatures may be needed for optimal performance.

In some embodiments, the devices and systems of the present inventionare controlled by a processor (e.g., computer software). In suchembodiments, a device can be configured to detect changes in activatedleukocyte levels within a subject and provide such information to theprocessor (e.g., information as to leukocyte level and/or increased riskfor developing an inflammation disorder). In some embodiments, when acertain activated leukocyte level is reached or a subject is deemed at acertain risk for developing an inflammation disorder (e.g., SIRS), thesubject's blood is processed through a SCID for purposes of reducing thepossibility of developing an inflammation disorder. In some embodiments,the device or system automatically processes the subject's blood throughthe SCID in response to these measurements. In other embodiments, ahealth professional is alerted to the elevated leukocyte level orincreased risk within the subject, and the professional initiates thetreatment.

It is contemplated that the devices of the present invention can beincluded with various kits or systems. For example, the kits or systemsmay include the devices of the present invention or various parts of thedevices, for example, hollow fiber hemofilter cartridges, leukocyteinhibiting agents (e.g., calcium chelating agents, such as citrate),allographic cells (e.g., renal tubule cells), or other parts.Additionally, the kits or systems may be combined with various surgicalinstruments necessary for implanting the filtration device into asubject.

3. Sequestration of Cells Associated with Inflammation

While the systems and devices of the present invention should beconfigured to sequester leukocytes from a subject and ameliorate (e.g.,inhibit) their inflammatory activity (e.g., inflammatory response), thesystems, devices, and methods of the present invention are not limitedto a particular design or technique for sequestering a leukocyte andfacilitating inhibition of release of a pro-inflammatory substance froma leukocyte and/or deactivation of a leukocyte. Sequestration ofleukocytes (such as activated and/or primed leukocytes) can be achievedwith any system, device, or component thereof. The terms “sample” and“specimen” are used in their broadest sense. On the one hand, they aremeant to include a specimen or culture. On the other hand, they aremeant to include both biological and environmental samples. These termsencompass all types of samples obtained from humans and other animals,including but not limited to, body fluids such as urine, blood, serum,plasma, fecal matter, cerebrospinal fluid (CSF), semen, and saliva, aswell as solid tissue. However, these examples are not to be construed aslimiting the sample types applicable to the present invention. The termsample in the context of the present specification frequently refers toblood from a subject. The term “blood” refers to any aspect of theblood, for example, whole blood, treated blood, filtered blood, or anyliquid derived from blood.

In the systems or devices of the present invention, one or morepassageways for flowing a biological sample, or one or more regionsthereof, can be configured in any of a variety of ways to sequesterleukocytes. If more than one passageway is used, they can be positionedin series and/or in parallel. In some embodiments, one or morepassageways may be contained within a cartridge, for example adisposable cartridge. A passageway or a passageway region can be definedby any number of surfaces, for example, 1, 2, 3, 4, 5, 10, 20, 50, 100,or more surfaces. Examples of surfaces include, but are not limited to,the walls of a device, such as cylindrical device walls and flat devicewalls, and/or the exterior surfaces of the hollow fibers describedherein.

The surfaces that define a passageway or passageway region can beselected from a variety of forms that sequester leukocytes. For example,flat surfaces (e.g., sheets), curved surfaces (e.g., hollow tubes orfibers), patterned surfaces (e.g., z-folded sheets or dimpled surfaces),irregularly-shaped surfaces, or other configurations can be used in apassageway (or a region thereof) configured to sequester leukocytes. Anyof these surfaces may include pores and be porous, selectively-porous,or semi-porous. For example, the surface can be a membrane. The term“membrane” refers to a surface capable of receiving a fluid on bothsides of the surface, or a fluid on one side and gas on the other sideof the surface. A membrane typically is porous (e.g., selectively-porousor semi-porous) such that it is capable of fluid or gas flowtherethrough. It is understood that the term “porous” as used herein todescribe a surface or membrane includes generally porous,selectively-porous and/or semi-porous surfaces or membranes. Moreover,additional surfaces in a passageway or passageway region (that may ormay not define the passageway) can facilitate leukocyte sequestration,such as particle (e.g. bead) surfaces, surfaces of one or moreprojections into the passageway, or surfaces of one or more membranesexposed to the flowing biological sample. These additional surfaces alsocan be selected from amongst the flat surfaces, curved surfaces,patterned surfaces, irregularly-shaped surfaces, and otherconfigurations described above and the materials described below, andcan have the enhancements described below.

Passageway surfaces or passageway region surfaces (e.g., the externalsurfaces of hollow fibers) that define and/or are part of a passagewayor passageway region configured to sequester leukocytes are not limitedto a particular type, kind or size, and may be made of any appropriatematerial. For example, a surface may be any biocompatible polymercomprising one or more of nylon, polyethylene, polyurethane,polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE),polyarylethersulfone, CUPROPHAN (a cellulose regenerated by means of thecuprammonium process, available from Enka), HEMOPHAN (a modifiedCUPROPHAN with improved biocompatibility, available from Enka),CUPRAMMONIUM RAYON (a variety of CUPROPHAN, available from Asahi),BIOMEMBRANE (cuprammonium rayon available from Asahi), saponifiedcellulose acetate (such as fibers available from Teijin or CD Medical),cellulose acetate (such as fibers available from Toyobo Nipro),cellulose (such as that are regenerated by the modified cupramoniumprocess or by means of the viscose process, available from Terumo orTextikombinat (Pirna, GDR) respectively), polyacrylonitrile (PAN),polysulphone, acrylic copolymers (such asacrylonitrile-NA-methallyl-sulfonate copolymer, available from Hospal),polycarbonate copolymer (such as GAMBRONE, a fiber available fromGambro), polymethylmethacrylate copolymers (such as fibers availablefrom Toray), and ethylene vinyl copolymer (such as EVAL, aethylene-vinyl alcohol copolymer available from Kuraray). Alternatively,a surface may be nylon mesh, cotton mesh, or woven fiber. The surfacecan have a constant thickness or an irregular thickness. In someembodiments, surfaces may include silicon, for example, siliconnanofabricated membranes (see, e.g., U.S. Patent Publication No.20040124147). In some embodiments, surfaces may include polysulphonefibers. Other suitable biocompatible fibers are known in the art, forexample, in Salem and Mujais (1993) Dialysis Therapy 2d Ed., Ch. 5:Dialyzers, Eds. Nissensen and Fine, Hanley & Belfus, Inc., Philadelphia,Pa. Cartridges comprising hollow fibers are not limited to particulardimensions (e.g., length, width, weight, or other dimension).

The passageway can include any combination of surfaces. For example, thesurface(s) of a passageway or passageway region can include anycombination of flat, curved, patterned, and/or irregularly shapedaspects. Moreover, a passageway or passageway region can be defined byor otherwise include surfaces of more than one material. Further, apassageway may include two or more regions. These different regions canhave the same or different surfaces.

As discussed above, one embodiment of the SCID that has been usedsuccessfully includes a housing containing hollow fibers. A passagewayfor blood is defined by the interior of the housing and the exterior ofthe hollow fibers. Leukocytes from the blood associate with a particularregion within the passageway, specifically, with the exterior surface ofthe hollow fibers. Accordingly, in certain embodiments, a passagewayregion configured to sequester leukocytes may include a porous membranethat permits smaller molecules to pass therethrough but forces largermolecules and/or cells to flow along the membrane. Moreover, in certainembodiments, the passageway region configured to sequester leukocytes isbounded by a surface of a housing and is bounded by, and may include,the exterior surface or surfaces of hollow fibers configured such thatthe biological sample (e.g., a subject's blood or filtered blood) flowsover these surfaces (i.e., over the hollow fibers). See, for example,FIG. 1. The hollow fibers may be porous, semi-porous, or non-porous anda different fluid (e.g., ultrafiltrate) may optionally flow or bepresent within the hollow fibers. The fibers can be formed from anysuitable material described herein.

In some embodiments, the systems, devices, and methods of the presentinvention are configured to sequester the leukocytes for any desiredamount of time, for example, from 1 to 59 seconds, from 1 to 59 minutes,from 1 to 24 hours, from 1 to 7 days, one or more weeks, one or moremonths, or one year or more. In some embodiments, the devices areconfigured to sequester leukocytes for an amount of time sufficient topermit the subsequent inhibition of release of a pro-inflammatorysubstance from the leukocytes and/or deactivation the leukocytes.

Any technique or combination of techniques that facilitatessequestration of the leukocytes can be used, including, for example,biological, chemical, mechanical and/or physical techniques. In someembodiments, biological or chemical techniques for sequestration can beused. Such techniques include using tissues, cells, biomolecules (forexample, proteins or nucleic acids), or small molecules to sequesterleukocytes. When a leukocyte is activated, selectins are produced by theleukocyte. This altered selectin production can facilitate bindingbetween the leukocyte and other leukocytes. In turn, the binding betweenleukocytes can increase selectin production in the additionally boundleukocytes, yielding exponential binding of leukocytes. Thus, selectinsmay be useful to enhance sequestration. Proteins, protein complexes,and/or protein components known to bind leukocytes include CD11a, CD11b,CD11c, CD18, CD29, CD34, CD44, CD49d, CD54, podocalyxin, endomucin,glycosaminoglycan cell adhesion molecule-1 (GlyCAM-1), mucosal addressincell adhesion molecule-1 (MAdCAM-1), E-selectin, L-selectin, P-selectin,cutaneous lymphocyte antigen (CLA), P-selectin glycoprotein ligand 1(PSGL-1), leukocyte functional antigen-1 (LFA-1), Mac-1, leukocytesurface antigen p150,95, leukocyte integrin CR4, very late antigen-4(VLA-4), lymphocyte Peyers patch adhesion molecule-1 (LPAM-1),intracellular adhesion molecule-1 (ICAM-1), intracellular adhesionmolecule-2 (ICAM-2), intracellular adhesion molecule-3 (ICAM-3),inactivated C3b (C3bi), fibrinogen, fibronectin, peripheral lymph nodeaddressin (PNAd), endothelial vascular adhesion protein 1 (VAP-1),fractalkine, CCL19, CCL21, CCL25, and CCL27. Other large molecules knownto bind leukocytes include hyaluronic acid, glycosaminoglycans (GAGs),and fucosylated oligosaccharides and their precursors. In certainembodiments, small molecules or adherents used to sequester a leukocytecan include, but are not limited to, peptides, such as peptidescomprising the amino acid sequence arginine-glycine-aspartic acid (RGD),and molecules comprising sialic acid. Accordingly, any of thesematerials can be used to enhance sequestration.

In use, any of these biological or chemical materials may be bound to asurface of a system or device of the present invention (e.g., within apassageway of a SCID) to facilitate or enhance sequestration.Alternatively or in combination, any of these materials may be insolution in a system or device of the present invention. In thisinstance, the materials may sequester leukocytes in conjunction withadditional techniques. For example, these materials may bind leukocytesin solution, agglomerating them to increase overall size relative to thesize of a single leukocyte. The agglomerated leukocytes then can becaptured with a membrane having a particular pore size.

In some embodiments, a system or device of the present inventionaccomplishes retention of leukocytes through control of mechanicalforces. For example, leukocytes may be sequestered on one or moresurfaces of (or in) a passageway or passageway region (e.g., the outsideof a porous hollow fiber) by utilizing a flow rate and deviceconfiguration that minimizes shear force between the leukocytes and thesurface(s), allowing the leukocytes to associate with the surface(s).Useful shear forces between the flowing leukocytes and the sequestrationsurface(s) include a shear force of less than 1000 dynes/cm², or lessthan 500 dynes/cm², or less than 100 dynes/cm², or less than 10dynes/cm², or less than 5 dynes/cm². Exemplary flow rates of bloodthrough systems and devices according to the invention that are usefulto achieve these shear forces include, for example, less than about 500mL/minute, from about 100 mL/minute to about 500 mL/minute, and fromabout 200 mL/minute to about 500 mL/minute.

In some embodiments, a device may physically retain the leukocytes, forexample, at one or more passageway surfaces, or regions thereof, byusing surfaces such as membranes or filters or by exposing theleukocytes to increased passageway surface area, for example, a surfacearea greater than about 0.2 m², or from about 0.2 m² to about 2.0 m², orfrom about 0.5 m² to about 1.0 m², or about 0.7 m², so as to increasethe amount of leukocytes that are sequestered and/or the time that aleukocyte is sequestered within the device.

In some embodiments, a system can achieve sequestration by subjectingthe leukocytes to a series of devices, for example, 2, 4, 10, 20, ormore cartridges (e.g., hollow fiber cartridges), each comprising one ormore sequestration passageways, or passageway regions, so as to increasethe length of the region configured to sequester the leukocytes and theresidence time of the leukocytes therein. In any of the aforementionedembodiments, the devices are configured to accomplish sequestration ofleukocytes in a manner permitting inhibition of release of apro-inflammatory substance from a leukocyte and/or deactivation of aleukocyte before, during, or after sequestering Inhibition of release ofa pro-inflammatory substance from a leukocyte and/or deactivation of aleukocyte can be achieved both during sequestration and during transportthrough a passageway, passageway region, or entire system of the presentinvention.

It should be understood that the sequestration techniques describedherein also can apply to platelets. In the case of platelets, similarbioglocial, chemical, mechanical and/or physical techniques as describedabove may be used to sequester platelets. In certain embodiments, agentsused to sequester platelets include one or more of glycoprotein Ibα(GPIbα), glycoprotein IIb (GPIIb), glycoprotein Ma (GPIIIa), CD41, CD61,von Willebrand Factor, β₂-integrin macrophage antigen-1, selectins suchas P-selectin, and a cell-adhesion molecule.

4. Inhibition and/or Deactivation of Cells Associated with Inflammation

The systems and devices of the present invention are configured, and themethods of the present invention are designed, to inhibit release of apro-inflammatory substance from leukocytes and/or deactivate leukocytes,such as primed or activated leukocytes, in a subject's blood such thatan inflammatory response within the subject is prevented and/ordiminished. Various techniques can be used. For example, in someembodiments, the devices and systems can inhibit release of apro-inflammatory substance from a leukocyte and/or deactivate aleukocyte by exposing the leukocytes (e.g., sequestered activated and/orprimed leukocytes) to leukocyte inhibiting agents. A leukocyteinhibiting agent can be bound, covalently or noncovalently, to a surfaceof a passageway, for example, a hollow fiber. Additionally oralternatively, a leukocyte inhibiting agent can be infused into thedevice or system before, during, or after sequestration of theleukocytes, for example, at or near a membrane surface. As mentioned,the proof-of-concept SCID treated leukocytes with citrate, leading toincreased subject survival.

The present invention is not limited to a particular type or kind ofleukocyte inhibiting agent. Leukocyte inhibiting agents include, forexample, anti-inflammatory biological agents, anti-inflammatory smallmolecules, anti-inflammatory drugs, anti-inflammatory cells, andanti-inflammatory membranes. In some embodiments, the leukocyteinhibiting agent is any material or compound capable of inhibitingactivated leukocyte activity including, but not limited to,non-steroidal anti-inflammatory drugs (NSAIDs), anti-cytokines, imatinibmesylate, sorafenib, sunitinib malate, anti-chemokines,immunosuppressant agents, serine leukocyte inhibitors, nitric oxide,polymorphonuclear leukocyte inhibitor factor, secretory leukocyteinhibitor, and calcium chelating agents. Examples of calcium chelatingagents include, but are not limited to, citrate, sodiumhexametaphosphate, ethylene diamine tetra-acetic acid (EDTA),triethylene tetramine, diethylene triamine, o-phenanthroline, oxalicacid and the like. The leukocyte inhibiting agent can be any protein orpeptide known to inhibit leukocytes or immune cells including, but notlimited to, angiogenin, MARCKS, MANS, Complement Factor D, the disulfideC39-C92 containing tryptic angiogenin fragment LHGGSPWPPC⁹²QYRGLTSPC³⁹K(SEQ ID NO: 1) and synthetic homologs of the same; the agent also can bethose proteins, peptides, and homologs reported by Tschesche et al.(1994) J. Biol. Chem. 269(48): 30274-80, Horl et al. (1990) PNAS USA 87:6353-57, Takashi et al. (2006) Am. J. Respirat. Cell and Molec. Biol.34: 647-652, and Balke et al. (1995) FEBS Letters 371: 300-302, that mayfacilitate inhibition of release of a pro-inflammatory substance from aleukocyte and/or deactivate a leukocyte. Moreover, the leukocyteinhibiting agent can be any nucleic acid known to inhibit release of apro-inflammatory substance from the leukocyte and/or deactivate theleukocyte. The leukocyte inhibiting agent can be in solution orlyophilized.

Any amount or concentration of leukocyte inhibiting agent can be used toinhibit the release of pro-inflammatory substances from a leukocyteand/or deactivate the leukocyte. The leukocyte inhibiting agent can beintroduced into a passageway, passageway region, device, device region,or system region of a system by any methods known in the art. Forexample, the leukocyte inhibiting agent can be infused at a port. Theamount of leukocyte inhibiting agent infused in a passageway can besufficient to inhibit release of a pro-inflammatory substance from aleukocyte and/or deactivate a leukocyte sequestered within the samepassageway or within an adjacent passageway. In some embodiments, aleukocyte inhibiting agent, for example, citrate, can be infused intothe system, a region of the system, or one or more devices within thesystem, including devices that perform other functions and do notsequester leukocytes. More particularly, the leukocyte inhibiting agent(e.g. citrate) can be infused upstream from, into, or downstream from apassageway that sequesters leukocytes. Alternatively, the leukocyteinhibiting agent can be contained in one or more passageways, passagewayregions, devices, or system regions within a system. For example, aleukocyte inhibiting agent can be bound to a surface in the passagewayconfigured to sequester leukocytes, or in another passageway, in anamount sufficient to inhibit release of a pro-inflammatory substancefrom the leukocytes and/or deactivate the leukocytes.

The inhibition of release of a pro-inflammatory substance from aleukocyte and/or deactivation of a leukocyte can occur temporallybefore, during, and/or after sequestration of the leukocyte. Moreover,the leukocyte can remain inhibited or deactivated for a period of timefollowing sequestration. In certain embodiments, a leukocyte can beinhibited or deactivated during the period of time that the leukocyte isexposed to a target concentration of a leukocyte inhibiting agent or isexposed to a target a concentration of Ca_(i) (typically from about 0.20mmol/L to about 0.40 mmol/L) that results from exposure to a leukocyteinhibiting agent such as citrate. The period of time that the leukocyteis exposed to the target concentration of leukocyte inhibiting agent ortarget concentration of Ca_(i) can precede, include, and/or follow theperiod of time that the leukocyte is sequestered. In certainembodiments, the leukocyte can continue to become or remain inhibited ordeactivated for a period of time following exposure to the leukocyteinhibiting agent.

The time of exposure to the leukocyte inhibiting agent can varydepending upon the agent used, the extent of leukocyte activation, theextent of production of pro-inflammatory substances, and/or the degreeto which the inflammatory condition has compromised patient health.Exposure can be, for example, from 1 to 59 seconds, from 1 to 59minutes, from 1 to 24 hours, from 1 to 7 days, one or more weeks, one ormore months, or one year or more. The leukocyte inhibiting agent can beapplied to the system before or during operation the system. In certainembodiments, the leukocyte inhibiting agent is applied during operationof the system and the amount of leukocyte inhibiting agent applied tothe system is monitored.

In some embodiments, a leukocyte inhibiting agent can be titrated intothe system (e.g., at a port 206 as shown in FIGS. 2A-2D and 3 or from afeed 435 and pump 436 as shown in FIGS. 4B, 4C, 4E, and 4F). Thetitration can be adjusted relative to a monitored blood characteristic.For example, citrate can be titrated into the system to keep the Ca_(i)in the blood at a certain level, for example, at a Ca_(i) concentrationof about 0.2 to about 0.4 mmol/L. Any type of citrate that isbiologically compatible can be used, for example, 0.67% trisodiumcitrate or 0.5% trisodium citrate. See, e.g., Tolwani et al. (2006)Clin. J. Am. Soc. Nephrol. 1: 79-87. In some embodiments, a secondsolution can be added into the system following inhibition of therelease of pro-inflammatory substances from a leukocyte and/ordeactivation of the leukocyte (e.g., at port 258 as shown in FIGS. 2A-2Dand 3, or from a feed 445 and pump 446 as shown in FIGS. 4B, 4C, 4E, and4F), to readjust the blood for reentry into the subject. For example, inembodiments in which a calcium chelating agent is used as the leukocyteinhibiting agent, calcium can be added back into the blood beforereentry into the subject.

In one embodiment, a 1000 mL bag containing a citrate solution, forexample ACD-A (Baxter Fenwal, Chicago Ill.; contents per 100 mL:dextrose 2.45 g, sodium citrate 2.2 g, citric acid 730 mg, pH 4.5-5.5 at25° C.) can be attached to an infusion pump and then attached to anarterial line (outflow from subject to devices) of the system (e.g. atport 206; the outflow from a subject in a CPB situation is called avenous line, and infusion occurs from, for example, the feed 435 andpump 436). A negative pressure valve can be employed to facilitatecitrate pump function (infusing into a negative pressure area proximalto the blood pump). The initial rate of citrate infusion can beconstant, for example, about 1.5 times, in mL/hour, the blood flow rate,in mL/minute (e.g., if the blood flow rate is about 200 mL/minute, thenthe initial constant rate of citrate infusion may be about 300 mL/hour).In addition, a calcium chloride infusion at a concentration of about 20mg/mL may be added near the venous port of the system (e.g., port 258;the analogous location in the CPB situation is shown as a feed 445 andpump 446 in FIGS. 4B, 4C, 4E, and 4F). The initial calcium infusion canbe set at 10% of the citrate infusion rate (e.g., 30 mL/hour). TheCa_(i) can be monitored continuously or at various times, for example,every two hours for the first eight hours, then every four hours for thenext sixteen hours, then every six to eight hours thereafter. Themonitoring can be increased as needed and can be monitored at more thanone location in the system, for example, after citrate infusion andafter calcium infusion.

Exemplary citrate and calcium chloride titration protocols are shown inTable 1 and in Table 2, respectively. In this embodiment, the targetCa_(i) range in the SCID is from about 0.20 mmol/L to about 0.40 mmol/L,with the Ca_(i) target concentration achieved by infusion of citrate(e.g., ACD-A citrate solution). As this is a dynamic process, the rateof citrate infusion may need to changed to achieve the target Ca_(i)range in the SCID. The protocol for doing so is shown below, withinfusion occurring at the infusion points described above.

TABLE 1 Citrate Infusion Titration Guidelines Circuit Ionized Ca²⁺(between the SCID and Infusion Adjustment with ACD-A citrate patient)solution (as described above) If circuit ionized Ca²⁺ is then decreasethe rate of citrate infusion by less than 0.20 mmol/L 5 mL/hour Ifcircuit ionized Ca²⁺ is then make no change to the rate of citrate0.20-0.40 mmol/L infusion (Optimal Range) If circuit ionized Ca²⁺ isthen increase the rate of citrate infusion by 0.41-0.50 mmol/L 5 mL/hourIf circuit ionized Ca²⁺ is then increase the rate of citrate infusion bygreater than 0.50 mmol/L 10 mL/hour

TABLE 2 Calcium Infusion Titration Guidelines Patient Ionized Ca²⁺ Ca²⁺Infusion (drawn systemically from patient) (20 mg/mL CaCl₂) AdjustmentIf patient ionized Ca²⁺ is then decrease the rate of CaCl₂ greater than1.45 mmol/L infusion by 10 mL/hour If patient ionized then decrease therate of CaCl₂ Ca²⁺ is 1.45 mmol/L infusion by 5 mL/hour (maximumallowable amount) If patient ionized then increase the rate of CaCl₂Ca²⁺ is 0.9 mmol/L infusion by 5 mL/hour (minimum allowable amount) Ifpatient ionized Ca²⁺ is then administer a 10 mg/kg less than 0.9 mmol/LCaCl₂ bolus and increase the rate of CaCl₂ infusion by 10 mL/hourDefault Range 1.0-1.2 mmol/L (preferred target level)

It should be understood that the deactivation techniques describedherein also can apply to platelets. In certain embodiments, agents usedto deactivate a platelet and/or inhibit release of a pro-inflammatorysubstance from a platelet include, but are not limited to, agents thatinhibit thrombin, antithrombin III, meglatran, herudin, Protein C andTissue Factor Pathway Inhibitor. In addition, some leukocyte inhibitingagents can act as platelet inhibiting agents. For example, calciumchelating agents, such as citrate, sodium hexametaphosphate, ethylenediamine tetra-acetic acid (EDTA), triethylene tetramine, diethylenetriamine, o-phenanthroline, and oxalic acid can deactivate a plateletand/or inhibit release of a pro-inflammatory substance from a platelet.

5. Indications

The methods, devices, and systems of the present invention can be usedfor treating and/or preventing a number of conditions that areassociated with inflammation. As used herein, the term “inflammatorycondition,” includes any inflammatory disease, any inflammatorydisorder, and/or any leukocyte activated disorder wherein the organism'simmune cells are activated. Such a condition can be characterized by (i)a persistent inflammatory response with pathologic sequelae and/or (ii)infiltration of leukocytes, for example, mononuclear cells andneutrophils, leading to tissue destruction. Inflammatory conditionsinclude primary inflammatory diseases arising within a subject and/orsecondary inflammatory disorders arising as a response to a medicalprocedure. The systems, devices, and methods of the present inventioncan treat any inflammatory condition for any subject. As used herein,the term “subject” refers to any animal (e.g., a mammal), including, butnot limited to, a human (e.g., a patient), a non-human primate, arodent, and the like, which is to be the recipient of a particulardiagnostic test or treatment.

Leukocytes, for example, neutrophils, are major contributors to thepathogenesis and progression of many clinical inflammatory conditions,including systemic inflammatory response syndrome (SIRS), sepsis,ischemia/reperfusion injury and acute respiratory distress syndrome(ARDS). Several different and diverse types of leukocytes exist;however, they are all produced and derived from a pluripotent cell inthe bone marrow known as a hematopoietic stem cell.

Leukocytes, also referred to as white blood cells, are found throughoutthe body, including in the blood and lymphatic system. There are severaldifferent types of leukocytes including granulocytes and agranulocytes.Granulocytes are leukocytes characterized by the presence of differentlystaining granules in their cytoplasm when viewed under light microscopy.These granules contain membrane-bound enzymes, which primarily act inthe digestion of endocytosed particles. There are three types ofgranulocytes: neutrophils, basophils, and eosinophils, which are namedaccording to their staining properties. Agranulocytes are leukocytescharacterized by the absence of granules in their cytoplasm and includelymphocytes, monocytes, and macrophages.

Platelets, or thrombocytes, also contribute to inflammatory conditions,as well as to homeostasis. Upon activation, platelets aggregate to formplatelet plugs, and they secrete cytokines and chemokines to attract andactivate leukocytes. Platelets are found throughout the body'scirculation and are derived from megakaryocytes.

The molecules that are primarily responsible for initiation of leukocyteand platelet adhesion to endothelium are P-selectin and von Willebrandfactor, respectively. These molecules are found in the same granules,known as Weibel-Palade bodies, in endothelial cells. Upon activation ofendothelial cells, the Weibel-Palade bodies migrate to the cell membraneto expose P-selectin and soluble von Willebrand factor at theendothelial cell surface. This, in turn, induces a cascade of leukocyteand platelet activity and aggregation.

Accordingly, the systems, devices, and methods of the present inventioncan treat and/or prevent any inflammatory condition, including primaryinflammatory diseases arising within a subject and/or secondaryinflammatory disorders arising as a response to a medical procedure(e.g., dialysis or cardio-pulmonary bypass). Examples of applicableinflammatory conditions, including inflammatory diseases and/ordisorders, include, but are not limited to, systemic inflammatoryresponse syndrome (SIRS), cardiopulmonary bypass syndrome, acuterespiratory distress syndrome (ARDS), sepsis, systemic lupuserythematosis, inflammatory bowel disease, pancreatitis, nephritis,multiple sclerosis, psoriasis, allograft rejection, asthma, chronicrenal failure, cardiorenal syndrome, hepatorenal syndrome, and any acuteorgan failure from ischemic reperfusion injury to myocardium, centralnervous system, liver, lungs, kidney, or pancreas.

Additional examples of inflammatory conditions include, but are notlimited to, transplant (such as organ transplant, acute transplant,xenotransplant) or heterograft or homograft (such as is employed in burntreatment) rejection; ischemic or reperfusion injury such as ischemic orreperfusion injury incurred during harvest or organ transplantation,myocardial infarction or stroke; transplantation tolerance induction;arthritis (such as rheumatoid arthritis, psoriatic arthritis orosteoarthritis); respiratory and pulmonary diseases including but notlimited to chronic obstructive pulmonary disease (COPD), emphysema, andbronchitis; ulcerative colitis and Crohn's disease; graft vs. hostdisease; T-cell mediated hypersensitivity diseases, including contacthypersensitivity, delayed-type hypersensitivity, and gluten-sensitiveenteropathy (Celiac disease); contact dermatitis (including that due topoison ivy); Hashimoto's thyroiditis; Sjogren's syndrome; AutoimmuneHyperthyroidism, such as Graves' Disease; Addison's disease (autoimmunedisease of the adrenal glands); Autoimmune polyglandular disease (alsoknown as autoimmune polyglandular syndrome); autoimmune alopecia;pernicious anemia; vitiligo; autoimmune hypopituatarism; Guillain-Barresyndrome; other autoimmune diseases; glomerulonephritis; serum sickness;uticaria; allergic diseases such as respiratory allergies (hayfever,allergic rhinitis) or skin allergies; scleroderma; mycosis fungoides;acute inflammatory and respiratory responses (such as acute respiratorydistress syndrome and ischemia/reperfusion injury); dermatomyositis;alopecia greata; chronic actinic dermatitis; eczema; Behcet's disease;Pustulosis palmoplanteris; Pyoderma gangrenum; Sezary's syndrome; atopicdermatitis; systemic sclerosis; morphea; trauma, such as trauma from agun, knife, automobile accident, fall, or combat; and cell therapy, suchas autologous, allogenic or xenogenic cell replacement. Additionalinflammatory conditions are described elsewhere herein or are otherwiseknown in the art.

The systems, devices, and methods of the present invention may also beused to support the development and use of tissues and organs ex vivo.For example, the present invention may be used to support organharvesting procedures for transplantation, tissue engineeringapplications, ex vivo generation of organs, and the manufacture of anduse of bio-microelectromechanical systems (MEMs).

In light of the foregoing description, the specific non-limitingexamples presented below are for illustrative purposes and not intendedto limit the scope of the invention in any way.

EXAMPLES Example 1 Treatment of Inflammation Associated with AcuteSepsis and Acute Renal Failure in an Animal Model

This example describes a series of experiments used to evaluate anembodiment of the present invention to treat inflammation associatedwith the conditions of acute sepsis and acute renal failure.

(I) Background and Rationale

Leukocytes, especially neutrophils, are major contributors to thepathogenesis and progression of many clinical inflammatory disorders,including SIRS, sepsis, ischemia/reperfusion injury and acuterespiratory distress syndrome (ARDS). A large number of therapeuticapproaches are under investigation to limit the activation and tissueaccumulation of leukocytes at sites of inflammation in order to minimizetissue destruction and disease progression. Severe sepsis with SIRSoccurs in 200,000 patients annually in the U.S. with a mortality rate of30-40%, even with use of intensive care units and broad spectrumantibiotics.

The origins of this research emanate from ongoing encouragingpre-clinical and clinical studies utilizing renal tubule progenitorcells in an extracorporeal device to treat acute renal failure (ARF).ARF arises from acute tubular necrosis (ATN) secondary to nephrotoxicand/or ischemic renal tubule cell injury in a cascade of eventsculminating in multi-organ failure and death. Mortality rates from ATNrequiring renal replacement therapy range from 50 to 70 percent. Thishigh mortality rate has persisted over the last several decades despitegreater understanding of the pathophysiology of the disorder andimprovements in hemodialysis and hemofiltration therapy.

The utilization of renal tubule progenitor cells as a therapy for theseconditions was based upon the thesis that renal tubule cells play animportant immunologic regulatory role in septic shock. Specifically,severe septic shock has been shown to result in acute tubular necrosis(ATN) and ARF within hours of bacteremia in a porcine model of septicshock. Thus, ARF develops early in the time course of septic shock, atime frame not appreciated clinically since it takes several days toobserve a rise in blood urea nitrogen and serum creatinine after theacute insult. The loss of the kidney's immunoregulatory function in ARFand ATN results in a propensity to develop SIRS, sepsis, multiorganfailure and a high risk of death. A recent report has demonstrated arise in sepsis events from 3.3% to nearly 60% in patients who developARF during the post-op course following open heart surgery.

The disorder of ARF, or ATN, may be especially amenable to therapy inconjunction with continuous hemofiltration techniques, since acutehemodialysis or hemofiltration alone has yet to reduce the mortalityrate of ATN below 50 percent, despite advances in synthetic materialsand extracorporeal circuits. ATN develops predominantly due to theinjury and necrosis of renal proximal tubule cells. The earlyreplacement of the functions of these cells during the episode of ATN,which develops concurrently with septic shock, may provide almost fullrenal replacement therapy in conjunction with hemofiltration. Theaddition of metabolic activity, such as ammoniagenesis and glutathionereclamation, endocrine activity, such as vitamin D3 activation, andcytokine homeostasis may provide additional physiological replacementactivities to change the current natural history of this diseaseprogression.

One system used to test the effects of renal tubule progenitor cells onthis condition consisted of a filtration device (a conventionalhigh-flux hemofilter) followed in series by a renal assist device (RAD),generally as described in U.S. Pat. No. 6,561,997. In those earlierexperiments, a RAD referred to an extracorporeal system utilizing astandard hemofiltration cartridge containing human renal epithelialcells grown along the inner surface of the fibers. This arrangementallowed the filtrate to enter the internal compartments of the hollowfiber network, lined with renal tubule cells for regulated transport andmetabolic function. Blood pumped out of the subject entered the fibersof the first hemofilter, where ultrafiltrate (UF) was formed anddelivered into the lumens of the hollow fibers within the RAD downstreamof the hemofilter. Processed UF exiting the RAD was collected anddiscarded as “urine.” The filtered blood exiting the initial hemofilterentered the RAD through the extracapillary space (ECS) port anddispersed among the fibers of the device. Upon exiting the RAD, theprocessed blood was returned to the subject's body via a third pump.That extracorporeal blood circuit was based upon blood pump systems andblood tubing identical to those used for continuous or intermittenthemodialysis therapy in patients with renal failure.

In vitro studies of renal tubule progenitor cells in the RADdemonstrated that the cells retained differentiated active transportproperties, differentiated metabolic activities and important endocrineprocesses. Additional studies showed that the RAD, when incorporated inseries with a hemofiltration cartridge in an extracorporeal bloodperfusion circuit, replaced filtration, transport, metabolic, andendocrine functions of the kidney in acutely uremic dogs. Furthermore,the RAD ameliorated endotoxin shock in acutely uremic animals.

To better understand the immunoregulatory role of renal tubule celltherapy, the tissue-specific consequences of sepsis with or without RADtherapy were evaluated with bronchoalveolar lavage (BAL). BAL specimenswere used to assess pulmonary microvascular damage and inflammation inresponse to SIRS. Preliminary data detailed below demonstrated thatrenal cell therapy was associated with less protein leak from damagedblood vessels and less inflammation.

With this experimental model system, the role of renal cell therapy onsystemic and tissue-specific inflammatory processes could be morecarefully evaluated in a second series of evaluations. At the same time,in the clinical trials evaluating the RAD, a barrier to enrollment wasthe requirement for systemic anticoagulation with heparin to maintainblood perfusion of the extracorporeal blood lines and dialysiscartridges. Over the last decade, to relieve the requirement forsystemic heparinization and better maintenance of blood perfusion incontinuous renal replacement therapy (CRRT) circuits, regionalanticoagulation with citrate as a calcium binder has become a standardtherapeutic modality.

Thus, a comparison in pre-clinical animal models using sham non-cellcartridges and cell-containing cartridges was performed to confirm thatcitrate and low Ca_(i) levels in the blood circuit did not reduce theefficacy of renal tubule cell therapy observed with systemic heparintreatment. As detailed below, citrate anticoagulation in a two-cartridgesystem showed profound and unexpected results.

(II) Experiment A—Initial Experiment of the Animal Model

To initially evaluate an embodiment of the present invention, anestablished reproducible model of SIRS in a porcine model of sepsis wasemployed. (See, e.g., Humes et al. (2003) Crit. Care Med. 31:2421-2428.)

Methods and Materials

Normal pigs (30-35 kg) were prepared by the introduction of appropriatecatheters to assess cardiovascular parameters and treatment withcontinuous venovenous hemofiltration (CVVH). The pigs then receivedintraperitoneally 30×10¹⁰ bacteria/kg body weight of E. coli. Within 15minutes after bacteria infusion, the animals were placed in a CVVHcircuit with two cartridges, the first being a hemofilter and the secondbeing a renal assist device (RAD) comprising porous, hollow fibers. Forthis experiment, the RAD refers to the device shown schematically inFIG. 7 in the circuit shown in FIG. 3. In FIG. 7, the RAD contains aplurality of membranes, which are hollow fibers 752 (only one is labeledfor clarity). The luminal space within the fibers is called theintracapillary space (“ICS”) 740. The surrounding space is called theextracapillary space (“ECS”) 742 within a housing 754 of the RAD. Bloodcontaining activated leukocytes enters the ECS inlet 748, moves into theECS 742 surrounding the fibers 752, and exits the RAD via the ECS outlet750, which enters into an outflow line. For this experiment, the hollowfibers 752 of the RAD are porous and contain allographic renal tubulecells, cultured in a monolayer on the lining of the lumen 740 of eachfiber. The control was a sham-RAD that contained no renal tubule cellsbut was otherwise the same as the RAD.

As shown in FIG. 3, blood exiting the animals was pumped into the fibersof the first hemofilter, where ultrafiltrate (UF) was formed anddelivered into the ICS 740 within the RAD hollow fibers 752 downstreamof the hemofilter. Processed UF exiting the RAD was collected anddiscarded as waste using a UF pump 304. The filtered blood exiting theinitial hemofilter entered the RAD through the extracapillary space(ECS) inlet 748 and dispersed among the fibers 752 of the device. Uponexiting the RAD via ECS outlet 750, the processed blood was returned tothe subject's body. The blood moved through the system via blood pumps204 and 300 placed before and after the hemofiltration device and athird blood pump (not shown in FIG. 3) placed between the RAD and theanimal. Citrate or heparin was added to the system at 206 and, ifnecessary, a second agent (to prepare the blood for re-entry) was addedat 258 before re-entry of the blood into the subject.

During the first hour following bacteria infusion, animals wereresuscitated with volume consisting of 80 mL/kg of crystalloid and 80mL/kg of colloid (Hepspan). At 15 minutes following bacteria infusion,animals received 100 mg/kg of the antibiotic Ceftriaxone to replicatethe clinical situation. No animals received vasopressor or inotropicagents.

Results and Discussion

Blood pressure, cardiac output, heart rate, pulmonary capillary wedgepressure, systemic vascular resistance and renal blood flow weremeasured throughout the study. Using this model, it was shown that RADtreatment maintained better cardiovascular performance over controls asdetermined by cardiac output and renal blood flow. The improved renalblood flow was due to a lower renal vascular resistance in RAD animalscompared to controls.

The improved cardiovascular parameters resulted in greater survivaltimes. Control animals (treated with a sham-RAD, which has no renaltubule cells) all expired within 7 hours, whereas all RAD-treatedanimals survived greater than 7 hours. The RAD group survived 10±2 hourscompared to 5±1 hour in the controls (p<0.02). Plasma levels ofinterleukin (IL-6), a prognostic inflammatory indication in septicshock, as well as interferon-gamma (IFN-γ), an initiator of the cytokineinflammatory response, were lower in the RAD group compared to thecontrol group.

The initial data demonstrated that the porcine model was a dependablemodel of acute septic shock and that RAD treatment improvedcardiovascular performance associated with changes in cytokine profilesand resulted in a significant survival advantage. The initial data alsodemonstrated that RAD therapy can ameliorate the multiorgan dysfunctionthat arises in septic shock.

To improve the reproducibility of this model, the volume resuscitationprotocol was increased from 100 mL/hour to 150 mL/hour immediately afterthe crystalloid/colloid bolus infusion at the time of bacteriaadministration. In addition to this improved resuscitation protocol, thetissue-specific consequences of sepsis with or without RAD therapy wereevaluated with bronchoalveolar lavage (BAL) to better understand theimmunoregulatory role of renal tubule cell therapy. BAL specimens wereused to assess pulmonary microvascular damage and inflammation inresponse to SIRS. It was shown that renal cell therapy was associatedwith less protein leak from damaged blood vessels and less inflammationin BAL fluid samples as well as improvement of other cardiovasculareffects of SIRS.

The above described refined animal model utilizing volume resuscitationwas used in a series of studies to evaluate if the efficacy of RADtherapy under citrate regional anticoagulation was similar to that undersystemic heparin anticoagulation. Thus, the comparison in pre-clinicalanimal models of sham RAD (non-cell) cartridges and RAD(cell-containing) cartridges was begun to assess whether citrate and lowCa_(i) levels in the blood circuit negatively affected the efficacy ofrenal tubule cell therapy observed with systemic heparin treatment.

Unexpectedly, the results showed that citrate anticoagulation using theRAD without renal cells (i.e., a SCID treated with citrate) waseffective in ameliorating the lung damage from SIRS and was almost aseffective in reducing the cardiovascular dysfunction and time to deathfrom septic shock in this large animal model, as detailed below.

(III) Experiment B—Large Animal Model Comparison of Systems Utilizing orLacking Renal Epithelial Cells

The improved porcine model of septic shock described above was used toassess the multi-organ effects of intervention with a renal assistdevice (RAD) versus a selective cytopheresis inhibitory device (SCID).In this experiment, both RAD and SCID refer to the device of FIG. 7 inthe circuit of FIG. 3, as described above. However, the RAD systemcontains porcine renal epithelial cells in the ICS 740 of the RAD 755and receives heparin anticoagulation treatment. The SCID system containsno cells in the ICS 740 of the SCID 755 and receives citrate treatment(with no heparin). The following data were derived from a total of 14animals. Seven animals were treated with sham controls, which were theRAD without porcine renal epithelial cells in the ICS and receivedheparin anticoagulation treatment, denoted as “Sham/Heparin” in FIGS.9-13. Four animals were treated with a RAD that included porcine renalepithelial cells and systemic heparin therapy, denoted as “Cell RAD” inFIGS. 9-13. Three animals were treated with a SCID that included nocells in the ICS and received citrate regional anticoagulation, denotedas “Sham/Citrate” in FIGS. 9-13.

Observations of Cardiovascular Parameters

As demonstrated in FIG. 9, the administration of bacteria describedabove into the peritoneal cavity induced a rapid, profound, andeventually fatal decline in mean arterial pressure (MAP) in all groups.The early data suggested that the SCID with citrate attenuated theeffect on MAP compared to sham/heparin control. The cardiac outputs (CO)are detailed for each group in FIG. 10. The CO was substantially higherin the RAD group compared to the other groups. The citrate effectreached significance with more animals, although it was less pronouncedthan the RAD effect compared to the sham/heparin controls. A similartrend among the groups was observed in stroke volume as well.

As an approximate measure of systemic capillary leak induced with thisseptic course, the changes in hematocrit are shown in FIG. 11. In FIG.11, the sham/heparin controls had a higher rate of increase with time,reflective of larger rates of volume loss from the intravascularcompartment in the sham control group compared to both the RAD and SCIDgroups. These changes were associated with a substantial survivaladvantage in the RAD and SCID groups at this preliminary evaluationstage compared to sham/heparin group (see, FIG. 12). The averagesurvival times were 7.25±0.26 hours for the sham/heparin group,9.17±0.51 hours for the SCID (sham/citrate) group, and 9.56±0.84 hoursfor the RAD (with cells in the ICS space) group. These data indicatedthat the RAD (with cells in the ICS space), and unexpectedly, the SCID,both improve cardiac output, renal blood flow and survival timescompared to the sham/heparin control.

Observations of Inflammatory Parameters

To investigate the effect of various therapeutic interventions with theporcine SIRS model, bronchoalveolar lavage (BAL) fluid was obtained atthe time of death and evaluated for protein content as a parameter ofmicrovascular damage, various inflammatory cytokines and the absolutenumber of polymorphonuclear cells (PMNs). As summarized in Table 3,preliminary data indicated that both RAD and SCID treatments resulted inless vascular damage and protein leak and less inflammatory cytokinerelease in the early phase of pulmonary involvement in SIRS. Levels ofIL-6, IL-8 and tumor necrosis factor (TNF)-α were lower in the treatmentinterventions versus sham controls. Levels of IL-1 and IL-10 were notdifferent. Absolute neutrophil counts in the sham controls were above1000 cells/mL, and the RAD and SCID groups trended lower, although then=1 or 2 in each group.

TABLE 3 Protein and Cytokine Levels in Bronchoalveolar Lavage (BAL)Fluid from Pigs with Septic Shock Protein TNF-α IL-1 IL-6 IL-8 (μg/mL)(pg/mL) (pg/mL) (pg/mL) (pg/mL) Sham Control 143 ± 11 21 ± 1 18 ± 2  63± 14 126 ± 42  (n = 6) RAD (n = 3)  78 ± 10 18 ± 5 18 ± 5 32 ± 6 33 ± 10SCD (n = 2) 110 ± 12 13 ± 2 14 ± 8 33 ± 2 84 ± 62 Note: Mean ± SE. BALperformed at time of death.

Observations of Leukocyte Sequestration

The hemodialysis literature suggests that blood circulation through thehollow fibers of a single cartridge results in a transient one-hourneutropenia response (see, e.g., Kaplow et al. (1968) JAMA 203:1135). Totest whether blood flow through the extracapillary space of a secondcartridge results in higher rates of adherence of circulatingleukocytes, total white blood cell (WBC) counts and differentials in theseptic animals were measured. The results are shown in FIG. 13.

As shown in FIG. 13, each group had a leukopenia response to theextracorporeal circuit, with a nadir developing at 2 hours andrecovering at 7 hours. The average differential counts from baseline to3 hours in these animals (n=1-2 in each group, total=5) are detailed inTable 4. All subsets of leukocytes declined, most prominently theneutrophils.

TABLE 4 Total WBCs Neutrophils Lymphocytes Monocytes Baseline (hour 0)15,696 6,422 6,792 306 Nadir (hour 3) 2,740 684 1,856 94 Note: Valuesare averages from 5 animals: 1 sham control, 2 RAD-treated, and 2SCD-treated animals.

To demonstrate the sequestration of leukocytes in the SCID, FIGS. 14A-Ddepicts the density of leukocyte adherence to the outer surfaces of thehollow fibers. These images demonstrate the sequestration of leukocytesin the SCID. Normal animals undergoing this treatment protocol do notdrop their WBC below 9,000 during an 8-hour treatment course, suggestingthat primed or activated leukocytes may be necessary to attach to thesecond membrane system.

These data confirm that the RAD improves cardiac output, renal bloodflow (data not shown) and survival times compared to sham/heparincontrols. Moreover, it was unexpected to find that the use of citrate incombination with a second, low shear force hollow fiber cartridge (i.e.,a SCID) had a large anti-inflammatory effect, even though it containedno cells in the ICS.

Example 2 In vitro Studies of Leukocyte Sequestration and Inhibitionand/or Deactivation

The experiment described in this example shows that leukocytes adheredto a dialysis membrane are inhibited and/or deactivated in the presenceof citrate. In addition, other data have demonstrated that citrateanticoagulation abolishes degranulation of neutrophils (acalcium-dependent event) during hemodialysis of subjects with end stagerenal disease (ESRD). To evaluate this process in more detail and expandit to other leukocyte populations and cytokine release, the following invitro experiments were performed.

Methods and Materials

Leukocytes were isolated from normal healthy individuals usingestablished methods. The leukocytes (10⁶ cells per well) were placedinto 12-well tissue culture plates containing 14×14 mm squares ofpolysulfone membranes (Fresenius, Walnut Creek, Calif.) and allowed toadhere for 60 minutes at 37° C. in RPMI media. The media was removed,cells washed with PBS, and the removed supernatants were analyzed forcell release. RPMI media with citrate (Ca_(i)=0.25 mmol/L) or withoutcitrate (Ca_(i)=0.89 mmol/L) was used to achieve the Ca_(i) levelsdescribed in Table 5 below. Each calcium condition also had media withor without lipopolysaccharide (LPS, 1 μg/mL) to activate the leukocytes.

The cells were exposed to these conditions for 60 seconds and removedfrom the media to assess release of lactoferrin (LF) and myeloperoxidase(MPO), proteins in exocytotic vesicles from neutrophils, and cytokines,IL-6 and IL-8, released from leukocytes. These compounds were assayedwith commercially available Elisa kits (R & D Systems, Cell Sciences,and EMD BioSciences).

Results and Discussion

The results are set forth in Table 5.

TABLE 5 Lactoferrin Myeloperoxidase IL-6 IL-8 (ng/mL/10⁶ cells)(ng/mL/10⁶ cells) (pg/mL/10⁶ cells) (ng/mL/10⁶ cells) BaselineStimulated Baseline Stimulated Baseline Stimulated Baseline StimulatedNormal Ca_(i) 205 416 437 886 3.9 4.4 29.9 35.0 (0.89 mmol/L) CitrateCa_(i) 221 187 268 270 3.3 2.9 25.8 19.4 (0.25 mmol/L) Note: WBCisolations from two different normal controls; each condition analyzedin duplicate. Baseline was without LPS; stimulated condition was withLPS (1 μg/mL).

The citrate-containing media with low Ca_(i) had no increases in LF,MPO, IL-6, or IL-8, in contrast to the normal Ca_(i) media, which hadsubstantial increases in these inflammatory proteins. These resultsdemonstrate that the stimulation of leukocyte populations adhered to adialysis membrane are inhibited and/or deactivated in the presence ofcitrate, which lowers the Ca_(i) level in the culture media. This lowCa_(i) level results in a change in cytosolic calcium levels to inhibitmultiple inflammatory responses in leukocytes (e.g. release of apro-inflammatory substance) and/or deactivate leukocytes.

Example 3 Treatment of Inflammation Associated with Acute Renal Failure(ARF) in Humans

The experiment described in this example shows the unexpected survivalrates in human subjects treated with an embodiment of the presentinvention, namely, a SCID including hollow fiber tubes is in a systemtreated with citrate versus those patients treated with a similar devicein a system treated with heparin. Specifically, in this experiment, SCIDrefers to a device of FIG. 7 in the circuit of FIG. 3. No renal cellswere included in the ICS of the SCID.

Background

The safety and efficacy of renal cell therapy on ten critically illpatients with ARF and multiorgan failure receiving continuous venovenoushemofiltration (CVVH) previously was investigated in Phase I/II trials(see, e.g., Humes et al. (2004) Kidney Int. 66(4):1578-1588). Thepredicted hospital mortality rates for these patients averaged greaterthan 85%. The devices used in the previously reported trial were seededwith human renal proximal tubule cells isolated from kidneys donated forcadaveric transplantation but found to be unsuitable for transplantationdue to anatomic or fibrotic defects. The results of this clinical trialdemonstrated that the experimental treatment could be delivered safelyunder study protocol guidelines for up to 24 hours when used inconjunction with CVVH. The clinical data indicated that the this systemexhibited and maintained viability, durability, and functionality in theclinical setting. Cardiovascular stability of the patients wasmaintained, and increased native kidney function, as determined byelevated urine outputs, temporally correlated with the treatment.

The system in the previous clinical investigation also demonstrateddifferentiated metabolic and endocrinologic activity. All but onetreated patient with more than a 3-day follow-up showed improvement, asassessed by acute physiologic scores. Six of the 10 treated patientssurvived past 28 days with kidney function recovery, although mortalityrates predicted for these 10 patients using the APACHE 3 scoring systemwere on average 85 percent. Plasma cytokine levels suggested that thiscell therapy produced dynamic and individualized responses in patientsdepending on their unique pathophysiologic conditions.

The favorable Phase I/II trial results led to subsequent FDA-approved,randomized, controlled, Phase II investigations at 12-15 clinical sitesto determine whether this cell therapy approach alters patientmortality. One Phase II study involved 58 patients, of whom 40 wererandomized to RAD therapy and 18 made up a control group with comparabledemographics and severity of illness by sequential organ failureassessment (SOFA) scores. The early results were as compelling as thePhase I/II results. Renal cell therapy improved the 28-day mortalityrate from 61% in the conventional hemofiltration-treated control groupto 34% in the cell-treated group (see, e.g., Tumlin et al. (2005) J. Am.Soc. Nephrol. 16:46 A). This survival impact continued through the 90-and 180-day follow-up periods (p<0.04), with the Cox proportional hazardratio indicating that the risk of death was 50% of that observed in theconventional CRRT group. This survival advantage with renal cell therapywas observed for various etiologies of ARF and regardless of organfailure number (1 to 5+) or the presence of sepsis.

Method

An additional study was undertaken to evaluate a commercial cellmanufacturing process and the addition of citrate regionalanticoagulation. The results of these patient treatment groups wereanalyzed to compare the mortality rates in patients treated with a SCID(no cells in the ICS) with systemic heparin anticoagulation or citrateregional anticoagulation. The device used in these experiments isschematically shown in FIG. 7 in the circuit depicted in FIG. 3 asdescribed above. However, for this experiment, the second blood linepump is between the SCID and the subject (not between the devices asshown in FIG. 3).

Results

Table 6 shows that the SCID/citrate system yielded marked increases insurvival rate at 28 days and between 90 to 180 days.

TABLE 6 Survival (N) 28 d (N) 90-180 d SOFA OF MOF Sepsis SCID/ 9/12 75%8/12 67% 11.9 3.8 2.6 58% citrate SCID/ 6/12 50% 3/12 25% 12.3 4.1 2.6558% heparin Note: SOFA = sequential organ failure assessment; OF = organfailure number; MOF = multiple organ failure number.

FIG. 15 graphically shows the marked increase in survival rate between 0and 180 days in patients treated with devices utilizing citrate(“SCID/citrate”) instead of heparin (“SCID/heparin”). These survivaldifferences occurred even though the patient groups had similar activityof disease as measured by SOFA scores and organ failure number. Neithergroup had cells in the ICS of the second cartridge of the system.

Discussion

This clinical impact was unexpected. These results providedunprecedented and surprising success in maximizing patient survival.Although these clinical data were derived from patients with ARF, it iscontemplated that the observation will apply more generally, forexample, to SIRS, ESRD and other inflammatory conditions. Furtherevaluation into potential mechanisms was accomplished with thehistological assessment of non-cell cartridges in the citrate- andheparin-treated groups. Similar to data from the animal models describedabove, the citrate/SCID system had the external surfaces of the hollowfibers of the second cartridge covered with white blood cells on theblood side of this cartridge. Similar binding was seen in theheparin/SCID system.

Example 4 Treatment of Inflammation with a One-Device System

In some instances, it may be beneficial to use a treatment system usinga single treatment device (i.e. a SCID without other treatment devices).As discussed previously, certain embodiments of the invention utilize afirst treatment device (e.g., a hemofilter) in an extracorporeal circuitthat may activate leukocytes (in an unwanted fashion) in addition toperforming its primary treatment function. The second treatment devicein the series, the SCID, achieves adherence and systemic sequestrationin the low-resistance compartment of the ECS (e.g., as shown in FIGS. 2Cand 2D). Thus, if the first treatment device is not needed to performits primary function, it may be beneficial to remove it and reduceunwanted activation of leukocytes. In other embodiments, such as sepsis,the circulating leukocytes may already be activated, and a single-deviceSCID system (e.g., as shown in FIGS. 2A and 2B) with the blood flowthrough the low-resistance compartment of the ECS may be adequate foradherence and sequestration of leukocytes. Only a single pump on thebloodline is needed with this circuit, simplifying the therapeuticintervention.

This experiment evaluates the effectiveness of selective cytopheresis,as well as survival rate and the effect of diminishing and/or preventingan inflammatory response, in a subject (e.g., an animal or human patienthaving an inflammatory response or at risk for developing aninflammatory response). Specifically, this experiment compares aone-device system having only a SCID in the system with a two-devicesystem having a SCID as well as other system components that treatblood, for example, one or more hemofiltration cartridges in the system.The one-device system can be particularly useful for subjects having orat risk of having conditions such as SIRS, in which leukocytesequestration and, optionally, leukocyte deactivation and/or inhibitionof release of a proinflammatory substance from a leukocyte, is a primarytreatment objective for the extracorporcal circuit. A two-device (ormultiple-device) system can be useful for subjects in need of more thanone treatment using an extracorporeal circuit, for example, for asubject with acute renal failure who needs both kidney dialysistreatment and leukocyte sequestration and, optionally, leukocytedeactivation and/or inhibition of release of a proinflammatory substancefrom a leukocyte.

A first test system will include a single SCID as shown in one of FIG. 5or 6 in the circuit of either FIG. 2A or 2B, respectively. A second testsystem will include a SCID as shown in one of FIG. 5 or 6 in themulti-device circuit of either FIG. 2C or 2D, respectively. For bothtest systems, the SCID hollow fiber cartridge or the entire system willcontain citrate. For both systems, ultrafiltrate and cells will not beincluded in the ICS of the SCID.

Two groups of subjects (e.g., pigs) will be administered bacteria toinduce sepsis and SIRS as described in Example 1 above. Each group willthen be treated with one of the test systems and measurements such asthose described in Example 1 will be taken. The measurements of the twogroups will be compared. In addition to the one-device and two-devicesystem configurations described, other configurations of the devices andsystems containing those devices may also be tested.

It is anticipated that the magnitude of transient leukopenia andneutropenia will be comparable between the one-device and two-devicesystems. The relationship of WBC counts and influence on cardiovascularand pulmonary functional parameters, systemic and pulmonary inflammatoryindicators, and change in leukocyte activation markers across thesingle-versus two-device systems will confirm whether the simplersingle-device system or the two-device system is beneficial insituations not requiring a second treatment device, although it isanticipated that both single-device and two-device configurations willbe effective.

Example 5 Comparison of Leukocyte Sequestration Surface Areas

This experiment evaluates the effectiveness of one or more SCID hollowfiber cartridges having different leukocyte sequestration surface areasin performing selective cytopheresis, to prevent an inflammatoryresponse, and to enhance survival rates in test subjects. Severalmembrane sizes will be tested. Initial tests will include a comparisonof SCID membranes with surface areas of about 0.7 m² and about 2.0 m²,respectively. Additional test groups can include comparisons of membranesurface areas between about 0.7 m² and about 2.0 m² and/or membranesurface areas greater than about 2.0 m².

In one study, SCIDs having hollow fiber cartridges with variousleukocyte sequestration surface areas, as described above, will beprepared. SCIDs of the general design of FIG. 5 will be placed in thecircuits of FIG. 2A or 2C, or SCIDs of the general design of FIG. 6 willbe placed in the circuits of FIG. 2B or 2D. Subjects (e.g., pigs) willbe administered bacteria to induce sepsis and SIRS as described inExample 1 above. Groups of the subjects will then be treated with one ormore of the systems described herein. For each system tested, at leasttwo different SCID membrane surface area sized (e.g., 0.7 m² and 2.0 m²)will be tested. Measurements such as those described in Example 1 willbe taken, and the measurements from each of the groups will be compared.

In another study, subjects (e.g. pigs or calves) undergoing CPB will bestudied. Treatment with CPB can cause organ dysfunction, including acutekidney injury (AKI) and acute lung injury (ALI). SCIDs having hollowfiber cartridges with various leukocyte sequestration surface areas,will be tested in a CPB circuit.

CPB will be performed on subjects as described in Examples 8 and 9herein with SCIDs configured in circuits as shown in any of FIGS. 4A-4F.For each system, at least two different SCID membrane surface area sizes(e.g., 0.7 m² and 2.0 m²) will be tested. Endpoint measurements willinclude those described herein, for example, in Example 1 or 8. Inaddition, the severity of CPB-induced AKI and CPB-induced ALI can beassessed as a function of SCID membrane sequestration surface area.

It is anticipated that increased membrane surface area will increaseleukocyte binding and cause a longer time interval of the leukopeniainduced with the SCID. Accordingly, it is anticipated that SCIDs withlarger sequestration surface areas (relative to smaller sequestrationsurface areas) will improve the effectiveness of selective cytopheresis(e.g., as measured by improved survival rate and/or improved effect ofdiminishing and/or preventing an inflammatory response) and will havegreater beneficial effects on alleviating complications associated withCPB, such as organ injury associated with CPB (e.g., AKI and ALI).

Example 6 A Selective Cytopheresis Device in a Septic Shock Model withAcute Kidney Injury

The experiments described in this Example describe pre-clinical testingof one-pump and two-pump systems with a SCID and either citrate orheparin administration in a porcine model of septic shock with AKI. Theexperiments generally were directed to two assessments. First, theexperiments assessed the efficacy of utilizing a SCID in a one-pumpcircuit (e.g., the SCID of FIG. 6 in the circuit of FIG. 2D) versus aSCID in a two-pump circuit (e.g., the SCID of FIG. 7 in the circuit ofFIG. 3). “One-pump” or “two-pump” refers to the number of pumps on theblood line of a circuit as shown, for example, by pump 204 in FIG. 2D (aone-pump system) or by pumps 204 and 300 in FIG. 3 (a two-pump system).An advantage to using a one-pump circuit is that existing dialysisequipment can be utilized without additional training or pump systems todeliver care at the bedside. In addition, the experiments assessed themechanism of action of the SCID to sequester activated leukocytes andinhibit their activation state using citrate versus heparin.

Materials and Methods

To assess the efficacy of the SCID in a one-pump circuit versus atwo-pump circuit, the following two test systems were prepared. First, aone-pump test system included the SCID of FIG. 6 in the circuit of FIG.2D. Second, a two-pump test system included the SCID of FIG. 7 in thecircuit of FIG. 3. Both test systems also included citrate or heparinand did not include cells in the ICS of the SCID.

The experiments in this example utilized the established porcine modelof septic shock with associated AKI and multiorgan dysfunction, asdescribed in Example 1. (See, e.g., Humes et al. (2003) Crit. Care Med.31:2421-2428.) Briefly, two groups of subjects (pigs) were administeredbacteria to induce sepsis and SIRS as described in Example 1 above. Eachgroup then was treated with one of the one-pump or two-pump testsystems. Each one-pump and two-pump system had two treatment subgroups,treatment with either citrate infusion or heparin infusion. Thus onegroup of subjects having sepsis and SIRS was treated with the one-pumpsystem and with either citrate or heparin; the other group of subjectshaving sepsis and SIRS was treated with the two-pump system and witheither citrate or heparin.

White blood cells, neutrophils, and platelets were measured to assessthe relative efficacy of the one-pump and two-pump systems. In addition,to assess the mechanism of action for the sequestration and inhibitionof activated leukocytes by the SCID with citrate versus heparin, severalparameters were measured in systems that used either citrate or heparin.The assessed parameters included myeloperoxidase (MPO) and CD11b, whichare indicators of neutrophil activation. For the measurement of CD11b,blood samples from animals were taken and a fluorescent antibody wasadded that binds to CD11b protein expressed on a leukocyte's cellsurface. The white blood cells were separated into various subsets withcell sorting, and the neutrophils in the neutrophil gate were thenanalyzed by fluorescent intensity, which is proportional to the numberof CD11b molecules on the surface that bound the fluorescent antibody.The entire neutrophil population was then analyzed, and the level ofactivation with CD11b expression was quantitatively assessed as meanfluorescent intensity (MFI). The assessed parameters also includedanimal survival.

Results

FIGS. 16A, 16B, and 17 show results of the effect of the one-pump andtwo-pump systems on leukocyte counts, neutrophil counts, and plateletcounts. Because leukocyte sequestration (FIG. 16A), neutrophilsequestration (FIG. 16B) and platelet sequestration (FIG. 17) weregenerally the same for citrate-treated and heparin-treated one-pumpsystems and for citrate-treated and heparin-treated two-pump systems,these figures display an average of the two one-pump subgroups ascompare to an average of the two two-pump subgroups. FIGS. 18-21 showthe results of the citrate-treated or heparin-treated systems. Becausethe measured characteristic for FIGS. 18-21 were generally the same forone-pump and two-pump systems treated citrate and for one-pump andtwo-pump systems treated with heparin, these figures display an averageof the two citrate subgroups as compared to an average of the twoheparin subgroups.

Two-pump versus one-pump test system comparison. To assess possibleeffects that pressure and/or flow differences between the one-pump andtwo-pump circuits might have on the sequestration of leukocytes in theSCIDs of the two test systems, white blood cell (WBC) and neutrophilcounts in the systemic blood were examined. The results for the one-pumpand two-pump systems relating to WBC and neutrophil counts are shown inFIG. 16A and FIG. 16B, respectively. As detailed in the Figures, nodifference was observed in these parameters between the one-pump system(n=5) and two-pump system (n=5).

Platelet sequestration. The platelet count was also assessed for animalstreated with either the one-pump or two-pump systems. As indicated inFIG. 17, both the one-pump and the two-pump systems with the SCID showeddecreased platelet counts for at least 9 hours following treatment withthe SCID. These data indicate that systems having a SCID sequesterplatelets.

Neutrophil activation. Activated neutrophils release various enzymes inresponse to invading microbes or tissue injury to initiate tissuerepair. The dominant enzyme released from neutrophil granules ismyeloperoxidase (MPO). Accordingly, systemic levels of MPO were measuredto indicate the level of neutrophil activation in subjects. FIG. 18shows that the average MPO levels in animals treated with the SCID andcitrate (SCID Mean; n=5) was lower than in animals treated with SCID andheparin (Heparin Mean; n=3). The level of neutrophil activation also wasquantitated by measuring the expression of CD11b, a membrane proteinresponsible for binding onto the endothelium as a first step to exitingthe circulation to a site of inflammation. As detailed in FIG. 19, athour 6 of sepsis induction, the MFI of neutrophils in the systemiccirculation was dramatically increased in the animals treated with theSCID and heparin (Heparin (Systemic); n=4) compared to the animalstreated with the SCID and citrate (Citrate (Systemic); n=4).

The analysis was further refined by assessing neutrophil MFI in thearterial and venous lines of the circuits to obtain an average acrossthe whole circuit. Samples were taken simultaneously from the arterialline of the circuit where blood exits the subject into the bloodline andfrom the venous line of the circuit where blood exits the bloodline andre-enters the subject. The difference in MFI (arterial-venous) in theheparin group (n=4) and citrate group (n=4) was dramatically differentat 3 and 6 hours, as shown in FIG. 20. This data suggests that citrateinfusion suppresses the level of neutrophil activation along thecircuit, which can be indicative of less activated circulatingneutrophils systemically for the same time periods.

Animal survival. The ultimate assessment of the efficacy of the SCIDwith citrate as compared to the SCID with heparin is the survivaleffect. As shown in FIG. 21, a consistent survival time advantage wasobserved in the citrate group, as compared to the heparin group. Themean survival time for animals treated with the SCID with citrate was8.38+/−0.64 hours (n=8), whereas the mean survival time for animalstreated with the SCID with heparin was 6.48+/−0.38 hours (n=11).

Additional assessments are contemplated. For example, data sets toevaluate the effect of the SCID with systemic heparinization versusregional citrate anticoagulation, or the effect of a one-pump ortwo-pump system can include: 1. cardiovascular parameters (heart rate;systolic, diastolic, and MAP; cardiac output; systemic vascularresistance, stroke volume; renal artery blood flow; central venouspressure; pulmonary capillary wedge pressure); 2. pulmonary parameters(pulmonary artery systolic and diastolic pressures, pulmonary, vascularresistance, arterial to alveolar O₂ gradient); 3. arterial blood gases(pO₂, pCO₂, pH, total CO₂); 4. complete blood counts (hematocrit(indirect measurement of capillary leak); WBC and Differential); 5.inflammatory indices (systemic serum levels of cytokines (IL-6, IL-8,IL-1, INF-γ, TNF-α)); and 6. pulmonary inflammation by BAL fluidparameters (protein content (vascular leak); total cell counts withdifferential; TNF-α, IL-6, IL-8, IL-1, INF-γ, neutrophil myeloperoxidaseand elastase; alveolar macrophages from BAL fluid and baseline andstimulated levels of cytokines assessed after LPS challenge). Inaddition, SCID inflammatory parameters (serum levels frompre-hemofilter, pre-second cartridge and post-second cartridge ofvarious cytokines (IL-6, IL-8, TNF-α, IL-1, INF-γ)) and neutrophilexocytotic compounds (myeloperoxidase, elastase and lactoferrin) can bemeasured to assess leukocyte activity, and simultaneous measurements ofthese elements also can be made in the UF pre- and post-second cartridgeto correlate with the blood and UF compartments during the progressionof treatment. Moreover, oxidative markers in serum and BAL fluid can bemeasured using gas chromatography and mass spectrometry to assessinflammation-induced oxidative stress in the various groups.

Conclusions

The data from the experiments confirm that an extracorporeal circuitthat includes a SCID and citrate treatment can effectively sequester andinhibit the release of a pro-inflammatory substance from, or deactivate,a leukocyte. Specifically, these data show that leukocyte sequestrationeffects are similar between the one-pump and the two-pump circuits. Inaddition, the SCID and citrate treatment system diminished the level ofneutrophil activation as compared to a SCID and heparin treatment systemin a septic shock animal model. The efficacy of the SCID and citratetreatment system resulted in increased survival time in a lethal animalmodel of sepsis. Moreover, both the one-pump system and the two-pumpsystem effectively sequestered platelets for at least nine hours. Basedon this data, it is contemplated that sequestration of platelets anddeactivating the platelets and/or inhibiting release of pro-inflammatorysubstances from the platelets may have beneficial effects similar tothose achieved by sequestering leukocytes and deactivating theleukocytes and/or inhibiting release of pro-inflammatory substances fromthe leukocytes as described throughout the description and examples.

Example 7 Treatment of End Stage Renal Disease in Humans

The experiment described in this example is designed to evaluatesurvival rates in human subjects treated with an embodiment of thepresent invention, namely, a cartridge comprising a hollow fiber tube ina system treated with citrate versus a similar system treated withheparin. The system configuration in this experiment will be the SCID ofone of FIG. 5 or 6 in the circuit of one of FIG. 2C or 2D, respectively,without cells in the ICS of the SCID. Methods and observations caninclude a comparison of the citrate versus heparin systems withoutadditional renal cells in the SCID cartridge.

Background

One example of disease associated with a chronic pro-inflammatory stateis end stage renal disease (ESRD). (see, e.g., Kimmel et al. (1998)Kidney Int. 54:236-244; Bologa et al. (1998) Am. J. Kidney Dis.32:107-114; Zimmermann et al. (1999) Kidney Int. 55:648-658). Dialysis,the predominant therapy, is focused on small-molecule waste removal andfluid balance. However, it does not address the chronic inflammationassociated with ESRD. In ESRD patients it is associated with severemorbidity and unacceptably high annual mortality rates of up to 21%(see, e.g., USRD System, USRDS 2001 Annual data report: Atlas ofend-stage renal disease in the United States, 2001, National Institutesof Health, National Institute of Diabetes and Digestive and KidneyDiseases: Bethesda. p. 561).

The life expectancy for patients with ESRD averages four to five years.Vascular degeneration, cardiovascular disease, poor blood pressurecontrol, frequent infections, chronic fatigue, and bone degenerationimpact significantly on the quality of life and generate high morbidity,frequent hospitalizations, and high costs. The dominant cause ofmortality in ESRD patients is cardiovascular disease, accounting fornearly 50% of overall mortality in ESRD (see, e.g., USRD System, USRDS2001 Annual data report: Atlas of end-stage renal disease in the UnitedStates, 2001, National Institutes of Health, National Institute ofDiabetes and Digestive and Kidney Diseases: Bethesda. p. 561), followedby infectious events.

ESRD patients develop a chronic inflammatory state that predisposes themto both cardiovascular disease as well as acute infectiouscomplications. ESRD patients are more susceptible to infection despiteadequate hemodialysis. Chronic hemodialysis induces a change in thepattern of cytokines equivalent to a chronic pro-inflammatory state(see, e.g., Himmelfarb et al. (2002) Kidney Int. 61(2):705-716;Himmelfarb et al. (2000) Kidney Int. 58(6):2571-2578), independent ofmembrane activation, inflammation, and clearance. These small proteinscan be hemofiltered, but plasma levels are not changed due to increasedrates of production (see, e.g., Kimmel et al. (1998) supra; Bologa etal. (1998) supra; Zimmermann et al. (1999) supra; Himmelfarb et al.(2002) supra; Himmelfarb et al. (2000) supra). Enhanced exposure tooxidative stress in ESRD patients undergoing hemodialysis furthercompromises the immune system and enhances susceptibility to infection(see, e.g., Himmelfarb et al. (2002) supra; Himmelfarb et al. (2000)supra).

Clinically, the chronic inflammatory state in ESRD patients is evidentby elevated levels of CRP, an emerging clinical marker, along withelevated levels of pro-inflammatory cytokines, including IL-1, IL-6, andTNF-α (see, e.g., Kimmel et al. (1998) supra; Bologa et al. (1998)supra; Zimmermann et al. (1999) supra). All these parameters areassociated with enhanced mortality in ESRD patients. Specifically, IL-6has been identified as a single predictive factor closely correlatedwith mortality in hemodialysis patients. Each picogram per milliliterincrease of IL-6 increases the relative mortality risk of cardiovasculardisease by 4.4% (see, e.g., Bologa et al. (1998) supra). Indeed, growingevidence suggests that the pro-inflammatory state is due to the primingand activation of neutrophils in patients with ESRD (see, e.g., Sela etal. (2005) J. Am. Soc. Nephrol. 16:2431-2438).

Method

Patients with end-stage renal failure will have their blood treated withan extracorporeal circuit comprising a hemofiltration device, a SCID,and citrate or, as a control, a hemofiltration device, a SCID, andheparin (i.e., the SCID of one of FIG. 5 or 6 in the circuit of one ofFIG. 2C or 2D, respectively, with citrate or with heparin treatment).The studies may also include within each SCID, renal tubule cells (sothat the SCID also acts as a renal assist device or RAD). Blood willflow from the patient to the hemofiltration device, to the SCID, andback to the patient. Appropriate pumps and safety filters may also beincluded to facilitate flow of the blood back to the patient.

Data sets to evaluate the effect of the SCID with citrate or heparinwill include SCID inflammatory parameters (serum levels frompre-hemofilter, pre-second cartridge and post-second cartridge ofvarious cytokines (IL-6, IL-8, TNF-α, IL-1, INF-γ)) and neutrophilexocytotic compounds (myeloperoxidase, elastase and lactoferrin), whichare measured to assess leukocyte activity across the various componentcartridges within the SCID. If a circuit with a SCID and UF is used(e.g., the SCID of FIG. 7 in the circuit of FIG. 3), simultaneousmeasurements of these elements will also be made in the UF pre- andpost-second cartridge to correlate with the blood and UF compartmentsduring the progression of treatment.

Results and Discussion

It is expected that ESRD patients whose blood is treated with theextracorporeal circuit comprising the SCID and citrate will showsignificantly better results as compared to ESRD patients treated withthe extracorporeal circuit comprising the SCID and heparin.Specifically, it is expected that the pro-inflammatory markers will belowered in patients receiving SCID with citrate treatment versus thosereceiving SCID with heparin treatment.

Example 8 A Selective Cytopheresis Device as Part of a CardiopulmonaryBypass Circuit

The experiments described in this example employed a single hemofiltercartridge as the SCID (e.g., the SCID shown in FIG. 5 or 6), which wasconnected to an extracorporeal circuit with blood flow (200 mL/minute)in a parallel circuit to a larger volume flow circuit. Citrate regionalanticoagulation was used to improve both anticoagulation of thisparallel circuit as well as a means to deactivate leukocytes, which weresequestered along the outer surface of the membranes within the SCID.

The protocol included an extracorporeal CPB circuit with a SCID in acalf model. The use of a SCID in each circuit had a temporal correlationto substantive falls in circulating leukocytes, predominantlyneutrophils. This decline was sustained throughout the procedureswithout breakthrough of the sequestration effect. Circuit designs foreasy incorporation of the SCID into the existing CPB circuits withoutsafety issues are shown in FIGS. 4B and 4C.

Background

Cardiac surgery advances have been absolutely dependent upon thetechniques for CPB. Unfortunately, it has been recognized that asystemic inflammatory response occurs in association with CPB, resultingin multiple organ dysfunctions following surgery. Multiple insultsduring CPB have been shown to initiate and extend this inflammatoryresponse, including artificial membrane activation of blood components(membrane oxygenator), surgical trauma, ischemia-reperfusion injury toorgans, changes in body temperature, blood activation with cardiotomysuction, and release of endotoxin. These insults promote a complexinflammatory response, which includes leukocyte activation, release ofcytokines, complement activation, and free-radical generation. Thiscomplex inflammatory process often contributes to the development ofALI, AKI, bleeding disorders, altered liver function, neurologicdysfunction, and ultimately multiple organ failure (MOF).

Pulmonary dysfunction is very common after surgery requiring CPB. Thisacute lung injury can be mild, with postoperative dyspnea to fulminantARDS. Nearly 20% of patients require mechanical ventilation for morethan 48 hours following cardiac surgery requiring CPB. ARDS develops inapproximately 1.5-2.0% of CPB patients with a mortality rate exceeding50%. Renal dysfunction with AKI is also a common occurrence in adultpatients after CPB. Up to 40% of these patients develop rises in serumcreatinine and BUN and in the 1-5% requiring dialytic support, thepost-operative mortality rate approaches 80%.

The mechanisms responsible for multiple organ dysfunction following CPBare numerous, interrelated and complex, but growing evidence suggests acritical role in the activation of circulating blood leukocytes,especially the neutrophil, in the development of ARDS in CPB-inducedpost-pump syndrome. Increasing evidence supports that the acute lunginjury in both ARDS and the post-pump syndrome is predominantlyneutrophil mediated following PMN sequestration in the lungs. Thesequestered and activated PMNs migrate into lung tissue, resulting intissue injury and organ dysfunction. Therapeutic interventions describedin the art that are directed toward leukocyte depletion during CPB havebeen evaluated both in pre-clinical animal models and early clinicalstudies. The results with leukocyte-depleting filters of the art havebeen inconsistent, with no reduction in circulating leukocyte countsduring CPB but mild improvement of oxygen requirements. No significantclinical improvement was seen in patients undergoing elective coronaryartery bypass graft (CABG) with a leukocyte-depleting filter of the art.In contrast, the systems, devices, and methods of the present inventionwill have beneficial effects, as described below. Depletion ofleukocytes with a blood separator may improve postoperative lung gasexchange function.

Methods and Results

Surgery was performed on each of three calves, identified as SCID 102,SCID 103, and SCID 107. Each calf (approx. 100 kg) was placed undergeneral anesthesia and connected to a CPB circuit in order to place aventricular assist device (VAD). CPB was accomplished between 60-90minutes with cardioplegia and aortic cross-clamping. The SCID was placedat the site depicted in either FIG. 4B or FIG. 4C, as identified belowfor each animal. Results of the three animals (SCID 102, SCID 103, andSCID 107) are summarized in FIGS. 22A-22F and 23A-23B.

Surgery details and results. For SCID 102, the circuit was set up as inFIG. 4B, with an F40 cartridge (Fresenius Medical Care, Germany) as theSCID in the circuit. As shown in FIGS. 22A-22F, declines were observedin leukocyte and platelet counts. As shown in FIG. 22E, there was adecline in eosinophil count, which may be important in acute lunginjury.

For SCID 103, the circuit was set up as in FIG. 4B, with a HPH 1000Hemoconcentrator (Minntech Therapeutic Technologies, Minneapolis, Minn.)as the SCID in the circuit. SCID treatment lasted 75 minutes, and anadditional sample was taken 15 minutes following the end of SCIDtreatment. As shown in FIGS. 22A-22E, time-dependent declines inleukocytes were observed. The SCID was disconnected at 75 minutes with adramatic rebound in neutrophils within 15 minutes. No clotting wasobserved.

For SCID 107, the circuit was set up as in FIG. 4C, with HPH 1000Hemoconcentrators (Minntech Therapeutic Technologies, Minneapolis,Minn.) used as each of the SCID and the hemofilter/hemoconcentrator inthe circuit. CPB was initiated 15 minutes before the SCID wasincorporated and SCID treatment lasted 45 minutes. An additional samplewas taken 15 minutes following the end of SCID treatment. As shown inFIGS. 22A-22F, leukocyte and platelet numbers declined beforeincorporation of the SCID into the circuit, and except for monocytes,declined further with introduction of the SCID. In this surgery,pressure profiles were obtained and a UF flow of 50 mL/minute wasdemonstrated.

As shown in FIGS. 23A and 23B, systemic Ca_(i) was maintained, and theSCID circuit Ca_(i) was in the target range. Of general note from thesesurgeries, no ultrafiltrate (UF) was observed with lower SCID pressures.

Conclusion

The experiments described in this Example suggest that incorporation ofa SCID device into an extracorporeal circuit, such as a CPB circuit, cansequester leukocytes and platelets and enhance the likelihood of asuccessful clinical outcome during surgery.

Example 9 Treatment of Inflammation Associated with CardiopulmonaryBypass-Induced Acute Lung Injury (ALI) and Acute Kidney Injury (AKI) inan Animal Model

As an extension of the experiments described in Example 8, theexperiments described in this Example are designed to show efficacy of adevice of the present invention to sequester leukocytes and inhibittheir inflammatory action in the treatment of CPB-induced ALI and AKI.

Specifically, the aim of this Example entails optimizing a SCID protocolthat effectively treats CPB-induced ALI or AKI. To achieve this goal,animals can be treated with any of the CPB circuits described in FIG.4B, 4C, 4E, or 4F, each of which includes a SCID and citrate feed.Alternatively, CPB circuits described in FIG. 4A or 4D can be tested,each of which includes a SCID without citrate infusion. Moreover, a SCIDused during CPB can be replaced with a fresh SCID while the treatment isoccurring, and/or one or more SCIDs can be placed in series or inparallel in the “SCID” location of any of FIGS. 4A-4F.

A variety of porcine models have been reported in the literature toassess the mechanisms and therapeutic interventions of CPB-induced ALI.For example, it has been demonstrated in prior porcine models thatdemonstrable ALI can be incrementally induced with additive insults,which include the following: (1) the length of time for CPB from 60 to120 minutes; (2) aortic cross clamping and cardiac cold cardioplegiaproducing ischemia/reperfusion injury; (3) cardiotomy suction with openreservoirs promoting activation of blood elements (leukocytes,platelets, and complement); and (4) endotoxin infusion post CPBpromoting a SIRS response similar to that observed in patients due todetectable levels of endotoxin post CPB, presumably due togastrointestinal barrier dysfunction following cardiac surgery and mildischemia/reperfusion injury.

An established porcine protocol of CPB-induced ALI with significantchanges in pulmonary function and molecular markers in bronchoalveolar(BAL) fluid within 3.5 hours following CPB and 2 hours post sequentiallipopolysaccharide (LPS; 1 μg/kg over 60 minutes) has been reported.This reported protocol uses a femoral-femoral hypothermic bypassprocedure followed by a 60-minute LPS infusion beginning 30 minutesafter CPB was discontinued. Lung parameters were measured up to 2 hoursfollowing these sequential insults, with significant injury parametersobserved. Other protocols could be developed to produce measurable ALIin 4 hours while being more reflective of clinical practice with CPB.

This example will use a clinically relevant model of ALI and AKIutilizing 60 minutes of CPB, aortic cross clamping and cardiachypothermic cardioplegia as the baseline protocol, along with cardiotomyand cardiac suctioning during CPB into an open venous reservoir topromote incremental insults. If this is not sufficient to causemeasurable ALI and AKI, then a 30-60-minute infusion of E. Coli LPS(0.5-1.0 μg/kg) beginning 30 minutes following completion of CPB will beadded. The general approach to this CPB porcine model is detailed below.

CPB Protocol

In one exemplary protocol, Yorkshire pigs (30-35 kg) are premedicatedwith IM atropine (0.04 mg/kg), azaperone (4 mg/kg), and ketamine (25mg/kg), and then anesthetized with 5 μg/kg of fentanyl and 5 mg/kg ofthiopental. After intubation with an 8-mm endotracheal tube(Mallinckrodt Company, Mexico City, Mexico), the pigs are placed in thesupine position. Anesthesia is maintained by continuous infusion of 5mg/kg/hour of thiopental and 20 μg/kg/hour of fentanyl. Musclerelaxation is induced with 0.2 mg/kg of pancuronium followed byintermittent reinjections of 0.1 mg/kg to achieve optimal surgical andventilatory conditions.

Ventilation is established using a volume cycle ventilator at 10 mL/kgtotal volume and an inspired oxygen fraction of 1 with no positive endexpiratory pressure. Polyethylene monitoring lines are placed in theexternal jugular vein and the femoral artery and vein. Esophageal andrectal temperature probes are inserted. Median sternotomy is performed.A 16 or 20 mm Transonic perivascular flow probe is placed on the mainpulmonary artery, and Millar microtip pressure transducers are placed inthe pulmonary artery and left atrium. Prior to initiating CPB, baselinepulmonary artery pressure and flow rate and left atrial pressurereadings are taken for determination of cardiac output. After systemicheparinization (300 U/kg), an 18F Medtronic DLP arterial cannula isplaced in the ascending aorta and a 24F Medtronic DLP single-stagevenous cannula is placed in the right atrium.

The CPB circuit is primed with 1,000 mL of lactated Ringer's solutionand 25 mEq of NaHCO₃. The circuit consists of a Medtronic BiomedicusCentrifugal blood pump, a Medtronic Affinity hollow fiber oxygenatorwith integral heat exchanger, and a cardiotomy reservoir. A MedtronicAffinity 38-μm filter is placed in the arterial limb to captureparticulate debris. The left ventricle is vented using a 12-Ga Medtronicstandard aortic root cannula with vent line connected to a Sams rollerpump and the cardiotomy reservoir. Scavanged blood is salvaged with acardiotomy suction catheter, also connected to the Sams roller pump andthe cardiotomy reservoir. Cardiopulmonary bypass is initiated,ventilation is discontinued, and systemic perfusion maintained at 2.4L/min/m² body surface area. Moderate perfusion hypothermia (32° C.rectal temperature) is used, and mean aortic pressure kept at 60-80 mmHgby modification of flow and intravenous phenylephrine infusion (0-2μg/kg/min). The ascending aorta is cross clamped, and cardioplegia isdelivered into the aortic root cannula at 7 degrees, consisting of theUniversity of Michigan standard cardioplegia solution diluted with bloodat a 4:1 ratio. The solution consists of citrate phosphate and dextrose(CPD), tromethamine, and potassium chloride. A total dose of 1 L ofcardioplegia is delivered, and 500 mL is repeated every 20 minutes.Systemic rewarming is started after 40 minutes, and extracorporealcirculation discontinued after 60 minutes (clamping time 45 minutes).Prior to weaning from CPB, the lungs are inflated to 30-cm H₂O airwaypressure for 10 seconds for three breaths, and the mechanicalventilation is resumed using the same ventilator settings. Duringweaning from CPB, an infusion of epinephrine (0-1 μg/kg/minute) istitrated to maintain aortic blood pressure within normal ranges. Within30 minutes of discontinuation of extracorporeal circulation, the bloodin the oxygenator is transferred back into the circulation, heparin isreversed by protamine (1 mg for 100 U heparin) and normothermic rectaltemperature achieved. Physiologic measurements are recorded before andduring CPB and for 4 hours after CPB.

Extracorporeal Circuit

With a porcine model of CPB with substantive changes reflective of ALIand AKI, the influence of the SCID in ameliorating organ injury can bedirectly tested. A single-cartridge SCID will be placed in a parallelcircuit after the membrane oxygenator (as shown, for example, in FIG.4F). It is contemplated that the membrane oxygenator will activatecirculating leukocytes, which are then sequestered in the SCID. Citratewill be added to the regional SCID parallel blood circuit to lower bloodionized Ca_(i) to target levels, for example, about 0.2 to about 0.4 mM,with Ca²⁺ reinfusion at the end of the parallel circuit. Two groups ofanimals will be evaluated and compared. The first group will receiveSCID and heparin anticoagulation, and the second group will receive SCIDand citrate anticoagulation. Each group will have six animals, withinitial analysis of the two groups after 3 animals from each group havebeen treated. Regional citrate anticoagulation will be achievedutilizing standard practice solutions and clinical protocols. Citrateacts as an anticoagulation agent by binding with calcium. The boundcalcium is then unavailable to trigger clotting factors. Calcium isadded to the bloodstream just before the blood is returned to the animalin order to restore systemic Ca_(i) levels that will allow adequatecoagulation and cardiac function.

The current standard protocol used for continuous renal replacementtherapy for citrate anticoagulation will be used. The ACD-A citrate IVsolution (Baxter Healthcare) will be connected to a citrate infusionpump and the line to the SCID blood infusion port prior to the SCID.Calcium will be administered into the returned blood after the SCID viaan infusion port to restore systemic calcium. Citrate infusion fluidrate (mL/hour) will be 1.5 times the blood flow rate (mL/minute) toachieve an Ca_(i) level pre-cartridge between 0.2 and 0.4 mmol/L.

The SCID blood flow rate is targeted to be 200 mL/minute and will becontrolled with a pump placed in the blood circuit pre-SCID set at aflow rate of 200 mL/minute. Calcium chloride (20 mg/mL, 0.9% N.S.) willbe infused into the blood line post-SCID to achieve an Ca_(i) level inthe system (animal bloodstream values) between 0.9 and 1.2 mmol/L.Initial Ca²⁺ infusion rate is 10% of the citrate infusion rate. Ca_(i)levels will be evaluated in the arterial end of the CPB circuit prior tothe pump system to reflect systemic Ca_(i) levels and in the venous endof the SCID parallel circuit. All Ca_(i) will be measured with ani-STAT® diagnostic device (Abbott Labs).

Measurement of Acute Lung Injury (ALI)

Pulmonary Function. ALI following CPB results in increases inalveolar-arterial oxygenation gradients, intrapulmonary shunt fraction,pulmonary compliance and pulmonary vascular resistance. These parameterswill be measured every 30 minutes during the 4 hour post-CPB period.

Lung Tissue Analysis. ALI in the post-pump syndrome is associated withneutrophil accumulation in the lung and increases in interstitial fluid.Neutrophil aggregation will be assessed at the end of the researchprotocol by obtaining lung tissue from a segment not used for BAL.Samples of tissue will be used for myeloperoxidase tissue activityreflective of tissue neutrophil infiltration, histologic processing forsemiquantitative neutrophil counts, and water weight in lung tissue,with the difference in weights prior to and after desiccation andexpressed as percent of wet weight [(wet weight−dry weight)/wet weight].

BAL Fluid Analysis. BAL fluid is obtained by cannulation of the rightmiddle lobe of the lung with three successive infusions of 20 mL ofnormal saline and gentle aspiration. The fluid is evaluated for proteincontent (reflective of microvascular injury) and cytokine concentration(IL-1, IL-6, IL-8, IL-10, IFN-γ, and TNF-α). Cell counts in the BALfluid are determined after a cytospin with cytology staining to providethe total and percentage of various cell components, includingepithelial, neutrophil, and macrophage/monocyte. Alveolar macrophageswill be isolated, incubated overnight and their cytokine response to LPSevaluated the next day. Fluid levels of matrix-metalloproteinase-2 and-9, elastase, and myeloperoxidase are measured with well-establishedassays as a reflection of activated neutrophil-secreted productsimportant in developing tissue injury.

Measurement of Acute Kidney Injury (AKI)

Recent clinical data have clearly demonstrated that neutrophilgelatinase-associated lipocalin (NGAL) is an early biomarker for AKIfollowing CPB. The amount of NGAL in the urine and serum at 2 hoursfollowing CPB is a highly specific and sensitive predictive marker ofAKI with subsequent increases in serum creatinine and BUN. Serum andurine will be collected at baseline, time of CPB discontinuance and qone hour after CPB in all animals. NGAL levels will be determined by asensitive ELISA assay for pig. Differences in NGAL levels should reflectthe degree of AKI in this animal model.

Serum chemistries will be measured with an automated chemical analyzer.Cytokine levels will be measured with commercial ELISA assay kitsreactive to porcine cytokines IL-1, IL-6, IL-8, IL-10, IFN-γ and TNF-α(R & D Systems). BAL fluid will be obtained for cell counts andcell-type distribution, protein as a measure of vascular leak, andcytokine levels, including IL-1, IL-6, IL-8, IL-10, IFN-γ and TNF-α

Cardiovascular and biochemical data will be analyzed byrepeated-measures analysis of variance (ANOVA). Plasma levels of variousmoieties, and survival times will be compared utilizing Student'sT-test, paired or non-paired as appropriate.

It is contemplated that animals receiving citrate regionalanticoagulation in the CPB system that includes a SCID will have lesspulmonary dysfunction, lung inflammation, and AKI as measured with NGAL.It is also contemplated that the degree of systemic WBC count withneutropenia and leukopenia will nadir at 3 hours but be of the samemagnitude in both groups. It is also contemplated that the release ofleukocytic inflammatory indices will be inhibited in the citrate versusheparin groups.

INCORPORATION BY REFERENCE

The entire disclosure of each of the publications and patent documentsreferred to herein is incorporated by reference in its entirety for allpurposes to the same extent as if each individual publication or patentdocument were so individually denoted.

EQUIVALENTS

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The foregoingembodiments are therefore to be considered in all respects illustrativerather than limiting on the invention described herein. Scope of theinvention is thus indicated by the appended claims rather than by theforegoing description, and all changes that come within the meaning andrange of equivalency of the claims are intended to be embraced therein.

What is claimed is:
 1. A system for treating activated platelets from asubject in need thereof, the system comprising: a device comprising ahousing defining a passageway that permits body fluid from the subjectto pass therethrough and a fiber or a plurality of fibers disposedwithin the housing, wherein each fiber has an exterior surface thatbinds the platelets; and a calcium chelating agent comprising citratepresent in an amount sufficient to inhibit the release of apro-inflammatory substance from the activated platelets or to deactivatethe platelets.
 2. The system of claim 1, further comprising a seconddevice in series with the device comprising the housing defining thepassageway.
 3. The system of claim 1, wherein the calcium chelatingagent is infused into the passageway.
 4. The system of claim 1, whereinthe surface that binds the platelets comprises a membrane.
 5. The systemof claim 4, wherein the membrane is porous.
 6. The system of claim 5,wherein the membrane permits the passage of fluid therethrough.
 7. Thesystem of claim 4, wherein the membrane has a surface area greater thanabout 0.2 m².
 8. The system of claim 4, wherein a surface of themembrane binds the platelets.
 9. The system of claim 1, wherein thedevice is configured such that shear force within the passageway is lessthan about 10 dynes/cm² when fluid passes through the passageway at arate of from about 100 mL/minute to about 500 mL/minute.
 10. The systemof claim 1, wherein the exterior surface that binds the plateletscomprises a cell-adhesion molecule that binds an activated platelet. 11.The system of claim 1, wherein the fiber is, or plurality of fibers are,hollow.
 12. The system of claim 1, wherein the device is cell-free. 13.The system of claim 1, wherein the device is configured to bind theplatelets for a time sufficient to permit the subsequent inhibition orrelease of a pro-inflammatory substance from the platelets and/ordeactivation of the platelets.
 14. The system of claim 1, wherein theexterior surface of the fiber binds the platelets.